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Definition
| The main energy-storing molecule used by cells. Any energy stored in ATP molecules is easily accessed to power any activity required by the cell. Structurally, it consists of an adenosine (the nucleotide adenine plus ribose) and three phosphates. It is unstable since all three phosphates are negatively charged and therefore repel each other. The transfer of phosphates to another molecule from ATP allows it to become a more stable molecule, with a net release of energy. |
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| Molecules through which protons flow, directly driving the phosphorylation of ATP. It is powered by the proton gradient established by the electron transport chain and is a trans-membrane protein. Oxygen acts as the final hydrogen acceptor, and combines with hydrogen to form a byproduct water molecule. From one molecule of glucose, 36 ATP are made. |
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| inhibits growth, closes stomates, induces seed dormancy. |
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| Absorption of Water and Nutrients by Roots |
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Definition
Lateral movement is the movement of water and solutes across a plant, accomplished via symplast and apoplast. The symplast is a continuous network of cytoplasms of cells connected via plasmodesmata. The apoplast is the network of cell walls and intracellular spaces that enables extensive extracellular movement of substances within a plant. Water can cross the epidermis in the symplast, but in the apoplast, it must cross by diffusion. A number of factors increase uptake of nutrients and water from the soil:
- Mycorrihizae: symbiotic structures on roots that intermingle hyphae of a fungus with the plant’s own roots, increasing the surface area and uptake.
- Rhizobium is a symbiotic bacterium that fixes nitrogen on plant roots. |
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| Acid rain is formed by pollutants in the air form combustion of fossil fuels. The pH of such rain is less than 5.6, and this can kill many lake-dwelling organisms and damage stone architecture. |
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| An impulse, or action potential, is an electrical signal that can only be generated in the axon of a nerve. When the threshold potential is overcome, sodium gate open and sodium floods in, drastically reducing the membrane potential, while at the same time the potassium gates open and potassium floods in, enhancing this reverse. This rapid depolarization is called an action potential. It is localized and lasts for only a short period. The refractory period is the time when the sodium-potassium pumps return the affected region to it’s original state. This ensures that a nerve can only respond to and transmit one signal at a time. The impulse moves along the axon propagating itself without losing any strength. If the axon is myelinated, the signal moves even faster because it jumps from node to node. |
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| Activation of the Specific Defenses |
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Definition
| Ways to activate the immune system: a macrophage engulfs a pathogen and presents a fragment of it to a class II MHC marker. It is acting as an APC cell. A specific helper T cell can be activated through the binding to the MHC-antigen complex. The activation process is enhanced by IL-1 and CD4 protein from the helper T cell. The activated helper T cell then proliferates; these clones secrete cytokines. The cytokines further stimulate helper T cells, B cells, and cytotoxic T cells. |
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| The transport of substances across the plasma membrane up their concentration gradient, and therefore requiring an active expenditure of energy on the part of the cell. There are quite a few examples of active transport. Plastoquinone in the thylakoids membrane of chloroplasts functions as a mobile electron carrier. The sodium-potassium pump pumps sodium and potassium ions across a cell membrane, pumping every three sodium ions for every two potassium ions. The electron transport chain in mitochondria consists of diverse proteins that pump protons across the cristae membrane. The contractile vacuole in some freshwater bacteria pumps out excess water. Exocytosis is the release of substances by vesicles across the membrane. Pinocytosis is the cellular ingestion of fluids. Parts of the membrane enclose around the dissolved substance and pinch inwards, creating a vesicle which draws in that substance. Phagocytosis is the engulfing of large particles of small cells by pseudo pods. Example: Macrophage devouring a pathogenic bacterium. Receptor-mediated endocytosis (endocytosis is the intake of molecules through the pinching of the membrane, exocytose, the outtake) enables a cell to take up large quantities of very specific substances. A ligand (a general term for a molecule that binds to a specific receptor site on the plasma membrane) binds to a specific receptor molecule on the plasma membrane and receptor-mediated endocytosis begins. The receptors migrate together and pinch in, forming a coated vesicle. |
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| Adaptations allowing plants to live on land |
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Definition
The biggest problems facing a plant on land are supporting the plant body and ensuring conservation of water. A myriad of adaptations including the following help to achieve this:
- cell walls made of tough cellulose support the plant
- roots and root hairs (Mycorrihizae) take up water and minerals from soil
- stomates open to absorb crucial gases and close to conserve water
- A waxy coating of cuticle and cutin help to conserve water
- gametes and zygotes form a protective coat called gametangia
- Sporopollenin is resistant to all kinds of environmental damage
- Seeds and pollen have a protective coat that prevents desiccation
- a reduced gametophyte generation
- the presence of xylem and phloem vessels enable the plants to grow tall
- lignin embedded in cell walls of xylem and other vessels helps support the plant |
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| The emergence of numerous species from a common ancestor introduced into the environment. All 13 species of finch near the Galapagos Islands are examples. |
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| Roots that arise in unexpected or unconventional places, such as above the soil. Roots that stick of above ground are called aerial roots. Prop roots are tall roots that help to prop up and support tall plants; an example is found in corn. |
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| Respiration (an energy-generating process) that occurs in the presence and by using oxygen. Releases more energy. Example: Cellular Respiration in mitochondria. |
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| Shows the relative numbers of individuals at each age. Zero population growth occurs when the number of people at each age group is about the same and the birth and death rates are about equal. |
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Definition
| Aggressive behavior. May involve actual aggressive actions as well as symbolic signals. |
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| The process by which certain cells convert pyruvate from glycolysis into ethyl alcohol and carbon dioxide in the absence of oxygen, and in the process oxidize NADH to NAD+. Used to make beer, hence the name. |
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Definition
| Hypersensitive immune responses to certain substances called allergens. Involves the release of histamines. Anaphylactic shock is a life-threatening reactions that can result in death rapidly. |
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| Speciation caused by geographic isolation, such as deserts, moutains, oceans, glaciers, canyons, lakes, rivers, lava plain, latitude, longitude, etc. |
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| Alternation of Generations |
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Definition
| Plants are characterized by an alternation of generations, whereby the diploid (2n) stage alternates with the haploid (n) stage. Depending on the species, either may be dominant. The gametophyte (n) produces gametes by mitosis. The Sporophyte (2n) produces gametes by meiosis. In angiosperms, the gametophyte exists inside the Sporophyte and is completely dependent on it. Meiosis occurs in the anthers (male) and pistils (female). Microspores become male gametes, megaspores female gametes. |
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Definition
An action that is unselfish, and according to AP Biology, increase the evolutionary fitness of their descendants or family while decreasing their own. Altruism evolves since it increases the number of copies of a gene common to a related group.
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| Respiration that occurs without oxygen. Releases less energy. Example: Alcoholic or Lactic Acid Fermentation. |
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Definition
| The centromeres of each chromosome seperate and the spindle fibers pull apart the sister chromosomes. SHORTEST PHASE OF MITOSIS. |
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| Any abnormal number of chromosomes resulting from nondisjunction. |
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Definition
Seed plants who bear flowers and fruits, which function as reproduction structures. Angiosperms are the most diverse class of plants, with over 90% of plant species. The color and scent of the flower works to attract pollinators, such as bees, that spread the pollen to other plants of the same species, thereby allowing fertilization to occur. After pollination and fertilization, the ovary becomes the fruit and the ovule becomes the seed. Fruit protects the dormant seeds. There are two main groups of angiosperms: monocots and dicots.
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Definition
| Some as above but segmented, digestive tract is a tube within a tube with a crop, gizzard, and intestine, has a Nephridia digestive tract, and a closed circulatory system, hemoglobin, diffusion of oxygen and carbon dioxide through moist skin, and have no gender. |
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Definition
| Medicines that kill bacteria or fungi. Many pathogens, recently however, have evolved immunity to many common antibiotics. |
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Definition
| Also called immunoglobins and are a group of globular proteins. Each antibody molecule is Y-shaped and has two identical heavy chains and two identical light chains, both of which are joined by disulfide bridges. Four unchanging or constant regions and four variable regions make up the core structure of an antibody. There are 5 classes of antibodies: IgM, IgA, IgD, IgE, IgG. They destroy free-floating pathogens through two major processes: the antibodies may neutralize the antigen by causing them to clump. This forms a large complex called an antigen-antibody complex that is then phagocytosed by macrophages. The other way is for the antibodies to activate complement, an array of proteins that assist in lysing pathogenic cells. The variety in antibodies is unlimited due to the variability of the human genome; no pathogen cannot be countered by antibodies. |
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Definition
| The grasshopper has a digestive tract similar to the earthworm, however, there are several differences. The grasshopper has specialized mouth parts for tasting, biting, and crushing food. The gizzard is made of plates of chitin that help to grind the food. The digestive tract is also responsible for removing nitrogenous waste (uric acid) from the animal. |
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Definition
| Protostomes coelomates that have jointed appendages and a segmented head, thorax, and abdomen, and have a chitinous exoskeleton. Open circulatory system with a tubular heart and hemocoels, Malpighian tubules for the removal of uric acids, trachea air ducts bring air, some have book lungs or book gills. |
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Definition
| The actions of humans to select livestock with more desired traits or advantages. |
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| Asexual / Vegetative Reproduction |
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Definition
| Plants form an genetically exact clone of themselves from vegetative parts of the plant, such as the root, stem, or leaf. Offspring from asexual reproduction lack genetic variety and adaptability but are more hardier; they can also thrive in highly stable environments. |
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Definition
| A type of learning where one stimulus becomes linked to another through experience. Two variants are classical conditioning and operant conditioning. The two are reviewed below. |
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Definition
| Atoms consist of subatomic particles, the most important being protons, neutrons, and electrons. Protons are positively charged and neutrons negatively charged, and they are equally balanced, leading the entire atom to be electrically neutral. |
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Definition
| Multiple sclerosis and lupus are two examples of autoimmune diseases. In this diseases, the extremely destructive immune system cannot distinguish between self and non-self. In the case of multiple sclerosis, the immune system attacks myelin sheath cells surrounding neurons in the immune system. |
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Definition
| Chromosomes containing traits not related to sex. |
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Definition
| a hormone that enhances apical dominance, and stimulates stem elongation. |
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Term
Avery, MacLeod, and McCarty
1944 |
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Definition
| Found that the transformationing agent is in fact a nucleic acid called DNA. They did this by seperating lipids, proteins, DNA, and RNA from heat-killed bacteria and found that some of the bacteria exposed to the DNA became virulent, while none of the bacteria exposed to the lipids, proteins, or RNA became virulent. This provided direct experimental evidence that DNA was the genetic material of life. However, they were ridculed and unaccepted by the scientific community of the time. |
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Definition
| A virus that infects or attacks bacteria cells. It is well understood and throughly reasearched. |
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Definition
| The presence of two or more phenotypically distinct forms of a trait in a single population of a species. Since either of the morphs, or different forms, are better suited to the demands of a certain area, both continue to survive and possibly in the future could reproduce, thus preserving genetic variation. |
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Definition
| A sympatric speciation in which extensive and complex ritual-like behavior seperates two species from reproducing. |
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Definition
| Most primitive animals exhibit radial symmetry, while most complex animals exhibit bilateral symmetry. The body is organized along a longitudinal axis with right and left sides that mirror each other (note, however, that they may not be exact). |
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Definition
| The main mode of bacterial reproduction that is asexual. Results in a population of bacteria that are all genetically identical, with the only source of genetic variation found in spontaneous but rare mutations. Even still, the rate of reproduction in bacteria is so rapid that the amount of resulting variation is significant. |
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Definition
| Affects a large portion of our daily lives. |
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Definition
| Continental drift is a theory that states that Pangea was a super continent that formed about 200 million years ago. Study of fossils and modern marsupials has confirmed this theory. |
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Definition
| A phenomena whereby organisms at higher trophic levels have greater concentrations of accumulated toxins in their bodies than those at lower trophic levels. A case in point is the Bald Eagle extinction during the 1950’s due to the presence of DDT in their prey. They were saved by human intervention. |
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Definition
| Most communities are dynamic instead of stable. Natural or man-made disasters can drastically change or destroy an entire ecosystem. What follows is the ecological rebuilding called succession. Primary Succession is when rebuilding begins in a lifeless area where even soil has been removed. The first organisms to inhabit such a barren area are pioneer organisms like lichens and mosses. Soil develops gradually, and once it does, more complex organisms like grasses and trees overwhelm the pioneer organisms. The final “stable” community is the climax community, and remains until a disaster, called a blow out. Secondary Succession occurs when an existing community has been cleared by some disturbance that leaves the soil intact. |
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Definition
| The study of living organisms whose bodies are made up of sacs containing chemicals called cells. |
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| Very large regions of the earth whose distribution depends on the amount of rainfall and temperature in the area. Each biome is characterized by different vegetation and animal life. The following is a review of the world’s major biomes. |
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Definition
| The dominant belief before the 1850's about inheritance whereby traits were blended toegether as passed on from generation to generation. |
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Definition
| A complex mechanism that beings with the release of clotting factors from platelets and damaged tissue. Anticlotting factors normally circulate in the blood vessels to prevent the buildup of plaque (a thrombus). A complex series of reactions trigger the formation of a blood clot in the case of external injury: Thromboplastin + CA2+ causes Prothrombin to activate to Thrombin, which causes Fibrinogen to activate to Fibrin, which forms blood clots at the site of the injury. |
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Definition
| The certain danger in a transfusion comes when the recipient has antibodies to the donor’s antigens. Cross-matches determine if this is a conflict. Blood Type O is called the universal donor because it has no blood cell antigens to be clumped by the recipient’s blood. Blood type AB is called the universal recipient because it cannot clump the donor’s blood. |
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Definition
| Arteries carry blood away from the heart at a high velocity and pressure. Arterioles are progressively smaller areas of arteries that transfer the blood over to capillaries. Since both move the blood at such enormous pressures, the walls are therefore made of thick, elastic, and smooth muscle. Veins carry blood at low pressures back to the heart. Venules are areas of capillary to vein transfer. Since veins have such low pressure, they have periodic valves that prevent backflow; they are also encased by skeletal muscle, which helps to move the blood. Capillaries are very thin (often unicellular) walls that allow for the diffusion of nutrients and wastes between the blood and surrounding cells. Blood cells travel in single file. |
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| Broad Definition of Plants |
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Definition
| Plants are defined as multicellular, eukaryotic, photosynthetic Autotrophs. Their cell walls are made of cellulose, and surplus carbohydrates are stored as starch. The reproductive lifecycle of plants is characterized by an alternation of generations, where the Sporophyte (2N) or gametophyte (N) is dominant, based on species. Most plants live on dry land, having been among the first multicellular organisms to do so. |
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Definition
| Plants with no vascular (transport) vessels of any kind. Were the first to evolve and are less common than tracheophytes. Examples include mosses. Due to the lack of xylem and phloem tissues, these plants must absorb water by diffusion. They also lack any lignin-reinforced tissue, meaning they are usually small and are restricted to moist environments. However, many bryophytes are surprisingly hardy, able to survive extremes of drought. Generally, the haploid (n) stage is dominant in the alternation of generations and the diploid (2n) stage is short-lived. These plants may also play a significant role in the ecosystem. Peat moss is used as fuel. |
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Definition
A general term for the overall movement of a fluid in one direction in an organism. In humans, blood is powered by bulk flow pumped by the heart; in trees, spa moves by bulk flow due to active transport in the phloem.
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Definition
| Fix carbon into 3-PGA by the enzyme rubisco. Not very efficient because rubisco binds with oxygen as well as carbon dioxide. C-3 Plants are quote “normal” plants and exist generally in moderate climates. |
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Definition
| An adaptation for hot and arid environments. Examples of C-4 plants are corn, sugar cane, and crabgrass. Carbon dioxide enters the mesophyll cells of a leaf and binds to PEP to form a 4-carbon oxaloacetate. PEP Carboxylase is the enzyme that catalyzes this reactions and, unlike rubisco, does not bond with oxygen, therefore avoiding the problem of photorespiration. The mesophyll cell then produces malic acid from oxaloacetate and pumps this through plasmodesmata into an adjacent bundle sheath cell. There it releases carbon dioxide into the Calvin Cycle. This is called the Hatch-Slack pathway. With the carbon dioxide inside the bundle sheath cell, a steep carbon dioxide gradient results between the airspace in the mesophyll of the leaf near the stomates. Kranz anatomy refers to the structural differences between C-3 and C-4 plants, meaning the bundle sheath cells lie under the mesophyll cells, deep within the leaf. |
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Definition
These plants keep their stomates closed during the day and open at night, an adaptation to extremely hot and arid climates. The mesophyll cells store carbon dioxide in organic compounds synthesized at night. At day, the Calvin Cycle incorporates the carbon dioxide into sugars.
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Definition
| A hormone produced in the duodenum, and that stimulates release of bile. |
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Definition
The main business of the light-independent or dark reactions. It is a cyclical process whereby the sugar PGAL is produced. Here are the following major points of the Calvin Cycle:
- Carbon fixation occurs during the start of the cycle.
- Carbon gains hydrogen, thus making the cycle a reduction reaction.
- Carbon Dioxide enters the cycle and immediately binds to a 5-carbon sugar, called RuBP. This is unstable and breaks down, catalyzed by the enzyme rubisco.
- Does not depend directly on light, but the products of the light reactions: ATP and NADPH, meaning it cannot proceed perpetually when not in direct sunlight. |
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Definition
| Cells which divide uncontrobally and do not exhibit contact inhibition. In addition, cancerous cells may contain an abnormally high number of chromosomes. |
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Definition
A key factor in promoting cell growth and division; the nucleus must be able to store enough information to produce adequeate quantities of genetic material for the needs of the cell. Some cells have thousands of nuclei. |
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Definition
| The protein coat of a virus. Surrounds the DNA or RNA genetic material of a virus. |
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Definition
| Always consist of three elements: carbon, hydrogen, and oxygen. The body uses carbs for quick energy, and are classified according to what sugars they contain. Monosaccharides, such as glucose, fructose, and galactose, are called simple sugars. Disaccharides consist of two Monosaccharides joined together by dehydration synthesis or condensation reactions. This occurs with the removal of one atom of water. Hydrolysis is the enzymatic addition of water molecules to compounds, breaking them down. Polysaccharides are polymers of carbs and are formed as many Monosaccharides joined together by dehydration synthesis. Examples include cellulose, starch, chitin, and glycogen. Cellulose is used to make up cell walls of plant cells. Starch is used as storage in plant cells (e.g. potato). Chitin makes up the exoskeleton of arthopods and the cell walls of mushrooms. Glycogen is used by animals to store energy, much like plant starches; in humans, this is stored in the liver and skeletal muscle. |
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Definition
| The reciprocal processes of photosynthesis and respiration form the basis of this cycle. Cellular respiration by animals and bacterial composers add CO2 to the air and removes O2 from the air. Burning of fossil fuels adds CO2 to the air. Photosynthesis removes CO2 from the air and adds O2. |
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Definition
| The limit to the number of individuals that can occupy one area at a particular time, due to resources and requirements. |
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Definition
| Individual cells must work together to perform all the tasks required by a complex multicellular organism. Cell junctions, signal transduction pathways, and cell-to-cell recognition are examples of this. Cell junctions are classified into four types: tight junctions, desosomes, gap junctions, and plasmodesmata. Tight junctions are belts around the epithelial cells that line organs and serve as a barrier to prevent leakage into or out of those organs. They are similar to rivets. Desosomes are found in many tissues and are analogous to welds holding cells together. They are commonly found in cells that undergo severe stress, like muscle cells. Gap junctions permit the passage of materials directly from the cytoplasm of one cell to the cytoplasm of another cell. They are similar to cell to cell tunnels. Plasmodesmata connect plant cells. Signal Transduction pathways are the transformation of a extracellular signal to a cellular response. Three stages occur: reception, transduction, and response. A signal molecule binds to a receptor molecule on the plasma membrane which undergoes a conformational change, which leads to transduction, where the message is relayed by a secondary messenger such as cyclic AMP to the appropriate area of the cell, where a response is generated. Cell-to-cell recognition is the cell’s ability to recognize and “sense” other cells around it. The extracellular matrix plays a crucial role in this communication. Contact inhibition is the normal trait of cells to stop dividing when they become too crowded. |
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Definition
| A regular sequence of growth and division undergone by normal healthy cells. Two important factors limit cell size and stimulate normal cell division: the volume to surface area ratio of the cell (affecting how fast the cell can take in nutrients and dispose of wastes) and the capacity of the nucleus to store genetic material. |
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Term
| Cell Cycle Control System |
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Definition
| Several checkpoints act as built-in stop signals that halt the cell's division until it is overridden by go signals. Three checkpoints exist in G1, G2, and M. The G1 checkpoint is known as the restriction point and is the major one in mammals. If a cell does not receive a signal here, it will go into the G0 phase, where no growth nor replication of DNA occurs first. The cycle is controlled by cyclins and CDK's. MPF was the first CDK discovered, and is called M-phase promoting factor. The frequency of cell division varies with the cell type. Most somatic cells are arrested in the G0 phase until stimulated to divide. Other cells, like stem cells, continually divide. |
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Definition
| An ultracentrifuge is used to spin liquid samples at high speeds, separating them into different layers based on density. Nuclei are spun to the bottom first, followed by mitochondria and ribosomes. |
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Definition
| Not found in animal cells. In plants and algae, the wall is constructed of cellulose; however, in fungi it is built of chitin. The cell wall provides protection against external pressures. The Primary cell wall is immediately outside the plasma membrane. The secondary cell wall is formed outside the primary cell wall. The middle lamella is a gluey layer formed between two dividing cells. |
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Term
| Centrioles, Centrosomes, and Microtubule Organizing Centers (MTOC’s) |
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Definition
| All lie outside the nuclear membrane, organize spindle fibers, and rise to the spindle apparatus required for cell division. Centrioles are not found in plant cells. |
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Definition
| A specialized region that holds the two chromatids together. |
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Definition
| Structures that help in animal cells to guide mitosis and consist of two centrioles. |
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Definition
| The organization of an animal in the specific order as follows: along with bilateral symmetry comes a front end (anterior) and a back end (posterior). This organization allows animals to move faster. Bilateral animals are all triploblastic, with ectoderm, endoderm, and mesoderm. |
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| Characterisitics of Mammals |
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Definition
| Mothers nourish offspring with mile, have hair and fur made of keratin, are homeotherms, the embryo develops internally connected to the mother via a placenta, and some dervie nutrients from within an egg. |
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| Characteristics Of Stable Populations |
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Definition
Hardy and Weinberg were two scientists who described a stable, nonevolving population, in which allelic frequencies do not change. According to the Hardy-Weinberg theory, if a population is stable, then the following must be true:
- the population must be very large.
- the population must be isolated from other populations of the same or similar species.
- there must be no mutations in the population.
- mating must occur randomly.
- there is no natural selection occurring in the population. |
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Term
| Characteristics of Primates |
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Definition
| Primates are probably descended from small, tree-dwelling mammals. They have dexterous hands and opposable thumbs, claws are replaced by nails, and hands and fingers have large numbers of nerve endings, eyes are front-facing and located closely together, primates usually have single births and are intensely involved in the rearing of their young for long periods of time. |
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Definition
| Occurs between molecules and when two atomic nuclei attract the same electron. Energy is released when a bond is formed, and energy is required to break a bond. Atoms bond towards having completed valence shells, that is, be stable. |
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Definition
| Have a double membrane and are only found in plants and algae. Three Types: chloroplasts, the sites of photosynthesis. Have inner membranes called Grana (consisting of discs called thylakoids). They are filled by a liquid called the stroma. Contain own DNA. A second type of plastid is leucoplasts, which store starch. Chromoplasts store carotenoid pigments, and are responsible for the various colors of plants. |
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Definition
| Deuterostome coelomates that have a notochord (a flexible rod that extends along the length of the body and acts as an axis), have dorsal and hollow nerve cords, tails aid in balance and movement, birds and mammals are homeotherms, and some are Poikilotherms. |
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Definition
| Tighly coiled and condensed strands of DNA. |
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Definition
| Humans have a closed circulatory system with arteries, veins, and capillaries. Blood is pumped by the heart and travels to the lungs, where it picks up oxygen, and then back to the heart and then to the rest of the body. Let’s trace the basic pathway of blood through the blood: blood enters the heart via the vena cava (superior, above the heart, inferior, below the heart). From there, it continues to the right atrium, and then through the AV value to the right ventricle. The blood is currently devoid of oxygen. It then passes through the pulmonary Semilunar valve to the pulmonary artery, which transports the de-oxygenated blood to the lungs. There the red blood cells take up oxygen, and the blood returns to the heart via the pulmonary veins. The blood flows into the left atrium and into the left AV valve into the left ventricle. The blood is oxygenated. The blood then passes through the aortic Semilunar valve to the aorta, the major artery supplying blood to the rest of the body. The blood travels to where it is supposed to, unloads oxygen, and then returns via the inferior or superior vena cava. |
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Term
| Circulation in Primitive Animals |
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Definition
| Primitive animals, such as the sponge and the hydra, have no circulatory system. Earthworms have a closed circulatory system. The grasshopper and other arthopods have an open circulatory system. After blood is pumped by the heart, it moves through spaces called sinuses. Arthopod blood is clear and lacks oxygen. |
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Definition
| Ivan Pavlov trained dogs by associating the sound of a bell to food; eventually the dogs salivated at the bell alone. |
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| Clonal Selection and Differentiation |
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Definition
| A fundamental mechanism in the development of immunity. Antigen molecules bind to specific B or T lymphocytes. The lymphocyte then becomes metabolically active, proliferates thousands of copies of itself, and differentiates into plasma cells and memory cells. Plasma cells are short-lived and provide an immediate response to the antigen. This is called the primary immune response. Memory cells are long-lived cells that bear receptors specific to the same antigen as plasma cells. They remain on alert in small numbers, patrolling the bloodstream for a lifetime. When they recognize the protein coat of that antigen, they re-activate. This response is more powerful and faster than the primary immune response. This is called the secondary immune response. The capacity of the immune system to generate a secondary response, even decades after initial contact, is called immunological memory. |
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Definition
Creatine exact copies of genes. Used for the following:
- to produce a protein product such as insuline
- te replace a nonfunctioning gene with a functioning copy (gene therapy)
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Definition
| Digestion occurs in the gastrovascular cavity, which has only a single opening. The gastro dermal cells lining the cavity secrete digestive enzymes into the cavity for extracellular digestion. |
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Definition
| Have the following characteristics: exhibit radial symmetry, has a polyp (vase-shaped) or medusa body plan, goes through a larva stage, then an asexual reproduction stage, and then finally a sexual reproduction phase. Has two cell layers: ectoderm and endoderm connected via the mesoglea, and has a gastrovascular cavity where extracellular digestion occurs, and also carries out intracellular digestion, has no transport system, and all members are stinging cells. |
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Term
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Definition
| Both traits show. For example, in the black / white whales example, the resultant offspring would have patches of white and patches of black on them rather than being all grey. |
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Definition
| A fluid-filled body cavity. Arises form the mesoderm and is completely surrounded by mesoderm tissues. Provides space from elaborate body systems such as a transport or respiratory system. Therefore, major organs and organ systems could not have developed without the Coelom. Some primitive animals have no Coelom and hence are called acoelomates. Nematodes are pseudo-acoelomates with a fluid-filled tube between the mesoderm and the endoderm. This acts like a hydrostatic skeleton, increasing the effectiveness of the animal’s muscular contractions during movement. |
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Definition
| The reciprocal evolutoinary set of adaptations of two interacting species. All predator-prey relationships are examples. |
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Definition
| Sex-linked recessive; rarely more than an annoyance. |
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Definition
| A symbiotic relationship where one organism benefits and the other is unaware of the other organism, but suffers no adverse effects. |
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Definition
| Homologous structures are structures on different species that have a common origin (wing of a bat, lateral fin of a whale, and the human arm). Analogous structures have the same function, but different forms (wing of a bat and wing of a fly). Vestigial structures are evidence that structures have evolved (appendix) and serve no purpose. |
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Definition
| Organisms that have a common ancestor will have common biochemical pathways. The closer related they are, the more closely similar their biochemical pathways will be. |
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Definition
| Related organisms go through similar stages in their embryonic development. |
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Definition
| GF Gause developed the competitive exclusion principle after studying interspecific in a lab. He worked with two species of paramecium. When they were separate, both populations grew rapidly and then leveled off. When the two populations were put together, however, one had the advantage and drove the other to extinction. His principle states that two species cannot coexist in a community if they shade a niche, that is, share the same resources. Whichever one has the slightest advantage will drive the other to extinction. Resource Partitioning is the evolution of one population to exploit different resources. Character displacement is the divergence in body structure, enabling a population to use different resources. Either, besides extinction of one of the species, is a possible outcome from competition. Competition is - / -. |
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Definition
| Scientists extract fully processed mRNA from cells and use the enzyme reverse transcriptase to make DNA copies of these RNA strands. This is cDNA. |
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Definition
The components of blood are the following:
Plasma is the liquid portion of the blood, which contains numerous substances. Red Blood cells, also called erythrocytes, carries oxygen and hemoglobin. Red Blood Cells do not have a nucleus and are short-lived; they are formed in the bone marrow and recycled in the liver. White Blood Cells, or leukocytes, fight infection and are formed in the blood. Platelets are cellular fragments are formed in the bone marrow from megakaryocytes. |
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Definition
| A primitive form of bacterial sexual reproduction. |
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Definition
| A reaction to overcrowding of cells; cells touching each other (contact) stop dividing to preserve room. |
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Definition
| When unrelated species share the same environment, and are subjected to similar evolutionary pressures, and subsequently show similar adaptations. A common example is the whale, which has the same stream-lined shape as many fish because they evolved in the same environment. |
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Definition
| Allows animals, usually members of the same species, to work together to achieve actions beyond the capabilities of a single individual. Example: wild dogs hunting together in a pack. |
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Definition
| A form of chemical bonding in which both atoms share electrons. The resultant structure of the atoms is called a molecule. Note how a molecule can only be formed by a chemical bond. If electrons are shared equally between atoms, the result is a nonpolar covalent bond. Diatomic molecules are formed by this kind of bond when the two atoms concerned are of the same element. Polar covalent bonds are covalent bonds where the electrons are shared unequally, that is, the electrons spend more time closer to one atom than the other. |
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Term
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Definition
OCCURS DURING PROPHASE I OF MEIOSIS I AND IS THE EXCHANGE OF GENETIC MATERIAL BETWEEN HOMOLOGOUS CHROMOSOMES, AND IS A MAJOR SOURCE OF GENETIC DIVERSITY AND VARIETY AMONG ORGANISMS. Produces recombinant genes inherited from both parents. An average of 2 to 3 crossover events occur per chromosome pair.
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Term
Crossing Over
On same chromosome |
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Definition
| The farther apart two genes are on one chromosome, the more likely a cross-over event will occur between them. The site at which a cross over and recombination occurs is called a chiasma. Crossover and recombination are major sources of variation in sexually reproducing organisms. |
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Term
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Definition
| Genetic disorder, autosomal recessive. Buildup of extracellular fluid in the lungs, digestive tract, and other major organs. Common in White Europeans. |
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Term
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Definition
| The actual dividing of the cytoplasm. It begins during anaphase. In animal cells, a cleavage furrow forms down the sides of the cells and pinches in between, seperating them. In plant cells, a cell plate forms during telophase and a sticky middle lamella connects them. |
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Definition
| stimulates cytokinesis and cell division. Inhibits protein breakdown, and therefore promotes growth. |
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Definition
| A complex network of protein filaments that extend throughout the cytoplasm and give the cell its shape, mobility, and anchors the organelles to the plasma membrane. Built of microtubules, which are hollow tubes that make up the cilia and flagella, as well as spindle fibers. Cilia and flagella use the 9+2 pattern. Spindle fibers help separate chromosomes during mitosis and meiosis and use a 9 triplets pattern. Microfilaments, also called actin filaments, support the shape of the cell. |
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Term
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Definition
| The molecule of DNA is formed into a double helical shape. One end runs from the 5' to the 3' end. The other runs antiparellel from the 3' to 5' end. It is a polymer of repeating units called nucleotides. These consist of a 5-carbon sugar (deoxyribose), a phosphate, and a nitrogen base, and are connected by phosphodiester bonds. |
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Term
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Definition
| An enzyme that catalyzes the elongation of the new DNA strands. It always progresses from the 5' to the 3', moving along the template strand. |
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Definition
| An enzyme that welds together Okazaki fragments on the lagging strand. |
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Term
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Definition
| Enzymes that make "cuts" in the DNA before the initiation of replication to ease the unwinding of the double helix. |
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Definition
| Usually bacteria and fungi; decomposers recycle nutrients back into the soil and then back into plants, thus allowing the food cycle to continue. |
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Term
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Definition
| A type of chromosomal mutation that is whn a fragment lacking a centromere is lot during cell division. |
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Term
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Definition
| The number of individuals per unit area or volume. Scientists use fairly accurate estimating techniques instead, such as mark and recapture. In this, organisms are tagged and then released. Later, the same process is repeated. Then the following formula is used: |
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Term
| Density-Dependent Inhibition |
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Definition
| When the environment of dividing cells beceomes crowded, cells stop dividing. |
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Term
| Depletion of the Ozone Layer |
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Definition
| The accumulation in the atmosphere of chlorofluorocarbons has caused the formation of a hole in the protective ozone layer, allowing more UV radiation to reach the earth, causing an increase in skin cancer worldwide. |
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Term
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Definition
| Less than 10 inches of rainfall a year, no unadapted plants can survive. Undergoes the most severe temperature fluctuations of any biome. Characteristic plants are adapted to environment, like cacti, that have extreme adaptations to conserve water. Most animals are only active at night, early morning, or late afternoon. Characteristic animals include rodents, kangaroo rats, snakes, spiders, insects, and lizards. |
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Term
| Details of the Muscle Cells |
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Definition
Every muscle consists of bundles of thousands of muscle fibers that are individually cylindrical muscle cells. Skeletal muscle consists also of modified structures that allow the cell to contract:
- the sarcolemma is a modified plasma membrane that surrounds each muscle fiber and can on its’ own generate an action potential.
- the sarcoplasmic reticulum (SR) is a modified ER that contains Ca++ needed for proper muscle contraction.
- the T system is a system of tubules that runs perpendicular to the SR and connects the SR to the extracellular fluid.
- The sacromere is the functional unit of the muscle fiber / cell. Z lines are it’s boundaries, which cause muscles to appear striated. |
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Term
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Definition
| More than two characterisitics are crossed for. The stereotypical phenotype ratio obtained by such a cross in 9:3:3:1. |
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Term
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Definition
| The 2n condition in the number of chromosomes. Maintains and shelters a hidden pool of alleles that may not be suitable fore present conditions but could later be advantageous. |
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Term
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Definition
| One phenotype replaces another in a population. See the insect example above. Directional selection can result in rapid shifts in allelic frequencies. An example is the antibiotic resistance of bacteria found in the past two decades. |
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Term
| Dispersion of Populations |
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Definition
The pattern of spacing of individuals within the area the population inhabits. The important patterns are shown below:
PATTERN CHARACTERISTICS
Clumped Small groups of some number e.g. 2000.
Uniform Relatively equal spacing of individuals.
Random Absence of any attractions or repulsions. |
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Term
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Definition
| Increases the extreme types in a population at the expense of the more moderate forms. This results in balanced polymorphism, a situation where a population is divided into two extreme phenotypic expressions of a given trait. |
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Term
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Definition
| Occurs when a population becomes isolated for any reason from the rest of the species, and becomes exposed to new evolutionary pressures, and subsequently evolves into a new species. Every form of both Allopatric and Sympatric Speciation result in Divergent Evolution. |
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Term
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Definition
| All are unicellular, prokaryotic, and includes extremophiles like the following. Methanogens obtain energy by the production of methane from hydrogen. Halophiles thrive in highly alkaline environments. Thermophiles dwell in areas with extremely high temperatures. These organisms have some introns, and no peptidoglycan walls. |
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Term
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Definition
| All are single-celled prokaryotes with no internal membranes. Many are pathogenic, and also act as decomposers; they play a vital role as instruments in genetic engineering, they have no introns, and include viruses because they fit no where else. Peptidoglycan walls. |
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Term
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Definition
| A diverse group that includes four of the major kingdoms: all have a nucleus and internal organelles, no peptidoglycan in cells, and are generally multicellular. |
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Term
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Definition
| Pecking orders that dictate where the animal belongs in the food chain. The top-ranked animal is usually the one with the best access to food, mates, and has the best fitness. |
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Term
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Definition
| 47 chromosomes (trisomy 21); causes mental retardation and other health defects. |
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Term
| Duchenne Muscular Atrophy |
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Definition
| Sex-linked recessive; progressive weakening of muscle control and loss of coordination. |
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Term
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Definition
The digestive tract is a long straight tube. Food is ingest by the mouth as the worm burrows deep underground. The food then moves to the crop, which functions in storage, and then to the gizzard, which grinds up the food. The presence of a large fold in the upper surface of the intestine called the typhlosole greatly increases the surface area.
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Term
| Echinodermata: Sea Stars and Sea Urchins (Invertebrates) |
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Definition
| Deuterostome coelomates that are sessile and that exhibit radial symmetry as adults, have a modified Coelom called a water vascular system and that creates hydrostatic support for tube feet, produce by sexual reproduction where the fertilization is external, also reproduces by fragmentation and regeneration, and sea stars also have a endoskeleton consisting of calcium plates. |
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Term
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Definition
| A proton pump in the mitochondria that uses the energy released from the exergonic flow of electrons to pump protons from the matrix to the outer compartment. This results in a proton gradient inside the mitochondrion. It makes no ATP directly, but provides the power needed for ATP synthase molecules. Oxygen acts as a final electron acceptor and is highly electronegative. NAD deposits electrons at higher levels than does FAD. The chain itself consists mainly of cytochromes similar to hemoglobin. |
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Term
| Elongation in Transcription |
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Definition
| The growth of the strand in transcription as RNA polymerase adds nucleotides in the 5' to 3' direction of a growing mRNA chain. The strecth of DNA transcribed to mRNA is called a transcription unit. Codon are units of triplets of bases that code for specific amino acids. |
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Term
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Definition
| Refers to the building of new DNA strands by DNA polymerases along the template strand in the 5' to 3' direction. |
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Term
Endocrine and Nervous Systems
Overview |
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Definition
| Two major regulatory systems that release chemicals: the endocrine system and the nervous system. The endocrine secretes hormones, while the nervous system secretes neurotransmitters. Epinephrine is an example of both a hormone and a neurotransmitter; it functions as the “fight or flight” response as a hormone and a neuro-messenger as a neurotransmitter. |
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Term
| Endoplasmic Reticulum (ER) |
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Definition
| A membranous system of channels and flattened sacs that traverse the cytoplasm. Rough ER is the site of protein synthesis due to attached ribosomes. Smooth ER assists in the synthesis of steroid hormones and other lipids, connects rough ER to the Golgi Apparatus, and carries out various detoxification processes. |
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Term
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Definition
| Enzymes are organic molecules, most commonly proteins but sometimes RNA molecules, that catalyze chemical reactions by lowering the necessary energy of activation. Organisms transform energy from one form to another in order to carry out essential life functions. These energy transformations are governed by the laws of thermodynamics. The first law of thermodynamics states that energy cannot be created nor destroyed, but only transferred. The second law of thermodynamics states that for every energy reaction, the universe becomes more disorganized (that is, the entropy increases). This is measured by the free energy equation: FREE ENERGY CHANGE=CHANGE IN TEMP (ABSOULTE TEMP)(ENTROPHY). Free energy is the energy available to do work. In cellular reactions, exergonic reactions drive endergonic reactions. Metabolism is the sum of all the chemical reactions that occur in cells. Catabolism breaks down molecules, anabolism builds molecules. Reactions occur in logical and precise sequences called pathways that allow the cell to harmoniously regulate the countless reactions within. Enzymes serve to speed up these reactions by lowering the amount of energy required to start a reaction. This is important because it allows the cell to regulate reactions by controlling when and at what rate they occur. If the potential energy of the products is greater than the potential energy of the reactants, than the reaction is endergonic; the reverse is also true. At a certain point, substrates are reacting with the enzymes at a rate so high that the enzyme reacts with another one just after another one nearly instantly. At this point, the rate of the reaction plateaus. A way around this is increasing the number of enzymes in the immediate area. Lets review the characteristics of enzymes. Enzymes are globular proteins that exhibit tertiary structure. Due to shape, enzymes are substrate specific. The induced-fit model describes how enzymes function. As the substrate fits with the enzyme, the enzyme adapts its shape, thus quickening the reaction. Enzymes are not used up by the reaction. Enzymes often require help from cofactors (inorganic) or coenzymes (vitamins). Proper enzyme functioning is affected by heat and pH levels. |
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Term
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Definition
| either is too extreme, the enzymes will denature and lose function. There are a few ways to inhibit enzyme activity. In competitive inhibition, some compounds resemble the normal substrate molecule and compete for the same active site on the enzyme as well as the substrate. These can be reversible or irreversible. In noncompetitive inhibition, the enzyme contains more than one active site and the substrate and inhibitor do not resemble each other. An operon is an example of noncompetitive inhibition, in which the binding of the repressor to the operator on the DNA blocks the binding site for RNA polymerase, and therefore no transcription can occur. Allosteric inhibition involves two active sites. When an inhibitor binds to a specific site, the enzyme undergoes a conformational change and the enzyme can no longer function. An example of this kind of regulation is phosphofructokinase, which catalyzes step 3 of glycolysis. It is inhibited by ATP molecules, thus making this a prime example of feedback inhibition, in which the product of a pathway inhibits that pathway itself, preventing a cell from wasting resources and energy. |
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Term
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Definition
| One gene masks the expression of another gene, and is said to be epistatic to the gene it masks. |
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Term
| Equation for the Complete Oxidation of Glucose |
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Definition
| C6H12O6 + 6O6 ----> 6CO2 + 6H2O + ENERGY |
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Term
| Ethical Considerations of DNA |
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Definition
SAFETY
May cause long-term health problems.
PRIVACY
Personal information on individuals can cause some to lose jobs, e.g. those with terminal or expensive genetic diseases.
EUGENICS
Margaret Sanger; improvement of human race. |
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Term
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Definition
| gas; promotes fruit ripening, cell death, leaf death. |
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Term
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Definition
| A later, more complex type of cell found in multicellular organisms that contains distinct compartmentalized organelles, DNA wrapped with histone proteins, large ribosomes, aerobic metabolism, specialized cell functions, and are much larger than prokaryotes (about 10 to 100 um). |
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Term
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Definition
| Eutrophication refers to the disruption of freshwater ecosystems as a result of human activities. Two things happen in order. First, organic material accumulates on the bottom of lakes, therefore reducing their depth. Second, detrivores use up as they decompose the dead organic matter. As more fish die, decomposers break them down more, and even more material accumulates at the bottom of the lake. Ultimately, this process continues until the lake disappears. |
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Term
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Definition
| Evolution is defined as the change in allelic frequencies in a population. Microevolution refers to all the changes in a single gene pool. Macroevolution refers to the appearance of a major development or new species. Phyletic Evolution (Anagenesis) occurs when a species so morphs into another that it is said to be a new species. Branching Evolution (Cladogenesis) occurs when a species branches out from a parent species. |
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Term
| Evolutionary Neutral Traits |
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Definition
| Traits that seem to have no selective value. Examples in human are blood type and fingerprint variation. |
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Term
| Evolutionary Trends in Animals |
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Definition
| Begin as tiny, primitive, unicellular organisms that previously dwelled in the oceans. About 1.5 billion years ago, the first multicellular eukaryotic organisms evolved. This marked the rise of new important trends: specialization of tissues, germ layers, body symmetry, cephalization, and body cavity formation. These will be discussed in detail below. |
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Term
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Definition
| When an atom absorbs energy, its’ electrons move to a higher energy level, and thus the atom is said to be in an excited state. |
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Term
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Definition
| The simplest model for population growth with unrestrained or unchecked growth. A population undergoing a period of exponential growth has no predation, parasitism, or competition. It has no immigration or emigration and is in an environment with unlimited resources. The human population has been in the exponential growth phase for over 300 years, although usually such growth is short-lived. |
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Term
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Definition
| The range of expression for mutant genes. An example is polydacty, or the prescene of multiple digits. |
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Term
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Definition
| Any gene not found in the nucleus, i.e. in the mitochondria and chloroplasts. Discovered in 1909 by Karl Correns. Defects in mitochondrial DNA can ause issues in ATP production. ALWAYS INHERITED FROM THE MOTHER. |
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Term
| Factors contributing to genetic variety among organisms |
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Definition
Independent Assortment of Chromosomes
Crossing Over
Random Fertilization |
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Term
| Familiar Hypercholesterolemia |
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Definition
| A genetically inherited disease in humans characterized by very high blood cholesterol levels. It is caused by absent or defective cholesterol receptors, and thus large amounts of cholesterol are never taken up by cells and remain in the blood, causing tons of problems. |
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Term
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Definition
| A self-regulating mechanism that increases or decreases the level of a particular substance. Positive Feedback enhances an already existing response. Negative Feedback maintains homeostasis. |
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Term
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Definition
| Fermentation, or anaerobic respiration, is a process of ATP production in environs devoid of oxygen that consists of both glycolysis and either Lactic Acid fermentation or Alcoholic fermentation. There are two types of organisms that predominantly use anaerobic respiration: Facultative Anaerobes, which con tolerate the presence of oxygen but simply do not use it; and Obligate Anaerobes, which cannot live in an environment with oxygen. As long as there is a adequate supply of NAD+ to accept electrons, fermentation can continue to generate ATP through glycolysis. Alcoholic and Lactic Acid fermentation are the reactions that regenerate NAD+ so that glycolysis can continue. Note: usually unicellular prokaryotes only make ATP through fermentation, which gives off far less ATP. |
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Term
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Definition
| Ferns are seedless tracheophytes that are also homosporous, meaning they produce only a single type of spore that is bisexual and gametophyte. Ferns are still restricted to moist habitats. The diploid (2n) stage is larger and more prominent than the haploid (n) stage: basically what you think of as a fern. The ancient ancestors of modern ferns grew to enormous heights and absorbed vast quantities of carbon dioxide; now, those ancient plants fossilized, and form the bulk of fossil fuels used today to drive the world. |
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Term
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Definition
| Holds the plant firmly in place and is a net-like structure common to monocots like grasses. Also helps to minimize soil erosion. |
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Term
| First Line of Nonspecific Defenses |
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Definition
| A physical barrier that helps to prevent pathogens from entering the body. The components of the first line are the skin, mucous membranes, cilia, and stomach acid. |
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Term
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Definition
| An innate, highly stereotypic behavior that once initiated is carried to completion, no matter what. FAPs are triggered by external sign stimuli; a releaser is when the signal comes from the same species. An example is the stickleback fish, which attacks other red-bellied males that enter its’ lands. Tinbergen discovered through numerous experiments that the sign stimuli / releaser was the red belly. |
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Term
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Definition
| Through the study of the fossil record we can determine the existence of species that have become extinct or evolved into different species. The earth is about 4.6 Billion years old. Archaeopteryx is a fossil that links reptiles and birds. |
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Term
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Definition
| Most common cause of mental retardation. Caused by an abnormal X chromosome and have the sequence CCG repeated >200 times. Dominant. |
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Term
| Freeze Fraction and Etching |
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Definition
| Used to study details of membrane structure. Involves rapid freezing by liquid nitrogen. |
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Term
| Frequency-Dependent Selection |
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Definition
| Also called minority advantage, this acts to decrease the frequency of the more common phenotypes and increase the frequency of the less common ones. |
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Term
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Definition
| The components of organic molecules most commonly involved in chemical reactions. These are attached to the carbon skeleton, and help diversify organic molecules. The functional groups are amino, carboxyl, hydroxyl, carbonyl, sulfhydryl, and phosphate. |
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Term
| Functions of Cell Division |
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Definition
| growth, repair, and replacement. |
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Term
| Gas Exchange in Humans and other similar mammals |
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Definition
| Needless to say, humans have an internal respiratory surface. Air enters through the nasal cavity and is moistened, warmed, and filtered. Air then passes down the larynx and trachea to the bronchi, and even further to the bronchioles. Alveoli are microscopic air sacs where diffusion of respiratory gases occur. The diaphragm contracts and lowers, thereby expanding the chest cavity, and thus the internal pressure inside the lungs is lower than outside. Therefore, air is drawn into the lungs by negative pressure. Dense networks of capillaries allow red blood cells to take up oxygen, and these then go on to supply the rest of the body. All of this is also true of closely related mammals. |
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Term
| Gas Exchange in Non-human animals |
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Definition
| Respiration is the exchange of gases between the organism and the surrounding environment. It is a passive process occurring by diffusion. Respiratory surfaces are therefore thin, moist, and have a large surface area. In simple animals, such as sponges and hydra, the entire body acts as a respiratory surface. Earthworks and flatworms have an external respiratory surface because diffusion of oxygen and carbon dioxide occurs at the skin. Oxygen is carried by hemoglobin. Grasshoppers and other arthopods and crustaceans have a internal respiratory surface. Air enters through the spiracles and travels through tracheal tubes, where diffusion occurs in sinuses. Oxygen is carried by hemocyanin in these organisms. Aquatic animals like fish have gills, that uses highly efficient countercurrent exchange to enhance the uptake. |
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Term
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Definition
| A cocktail of hormones and enzymes that break down all food and is produced, secreted, and contained within the stomach. |
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Term
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Definition
| hormone produced by the stomach wall and involved in the stimulation of secretion of gastric juice |
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Term
| Gated Channels in the Nervous System |
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Definition
| Gated-ion channels that open or close in response to a stimulus and therefore play an essential role in the transmission of electrical impulses. Sodium entering will cause the membrane potential to fall to -60mV, so that the nerve is easier to fire. Potassium entering will cause the potential to rise to -75mV, so that the nerve is harder to fire. |
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Term
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Definition
| Separates large molecules of DNA on the basis of their rate of movement through an agarose gel ; the smaller the molecule, the faster it moves. The smaller the piece of DNA, the farther it has traveled from the well. |
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Term
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Definition
| The movement of alleles into or out of a population. Can occur as the result of fertile individuals or gametes between populations. |
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Term
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Definition
| A form of Transduction that moves pieces of bacterial DNA randomly asthe pahge lyses one host cells and infects another during the lytic cycle. |
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Term
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Definition
| The change in the gene pool due to change. There are two examples are the bottleneck effect and founder effect. The bottleneck effect are natural disasters such as fires, earthquakes, and floods that unselectively reduce a population. Therefore, certain alleles may become more or less over or under representative. The founder effect occurs when a small population breaks away from a larger one to colonize a new area; this smaller population is most likely not genetically representative of the population before the incident. Rare alleles tend to be overrepresented. |
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Term
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Definition
| Certain traits whose expression varies according to which parent the trait is inherited from. |
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Term
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Definition
| Graded variation between two populations of a species due to arrangement along a geographical climate is called a cline. North-South clines are variations along a north to south plane. |
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Term
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Definition
| The main layers that form the various tissues and organs of the body. Formed early in embryonic development. Consists of the ectoderm, endoderm, and mesoderm in triploblastic complex animals. The ectoderm becomes the skin and nervous system. The endoderm becomes the viscera or the digestion system. The mesoderm becomes the blood and bones. Dipoblastic animals, like cnidarians, have only two cell layers, and have the mesoglea instead of the mesoderm. |
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Term
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Definition
| promotes stem and leaf elongation. Induces bolting. |
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Term
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Definition
Glial Cells are essential for the normal functioning of nerve cells.
Schwann cells are glial cells that form a myelin sheath around the axon of a neuron. |
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Term
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Definition
| Excessive burning of fossil fuels has apparently caused CO2 levels to rise in the atmosphere, thereby bringing about a “greenhouse” effect that warms the earth. This has been thrown into doubt by the “Climate-Gate” Scandals of 2010, which revealed many statistics were smudged, and many leading scientists behind the science of global warming had attempted to silence all opposition. |
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Term
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Definition
| The first step of aerobic cellular respiration, itself consisting of ten steps. Glycolysis breaks down one molecule of glucose, producing 4 ATP molecules through substrate-level phosphorylation and 2 molecules of pyruvate acid, which go on to the next step, the Krebs Cycle. Glycolysis can occur with or without oxygen. It occurs in the cytoplasm. 2 ATP are required to start Glycolysis, meaning there is a net gain of +2 ATP. Each step is controlled through the catalytic actions of enzymes, such as phosphofructokinase. Phosphofructokinase is inhibited by ATP; as Cellular Respiration produces more and more ATP, Glycolysis shuts down and cellular respiration halts. However, as the cell’s various activities use up ATP, Glycolysis again starts up uninhibited. This is an important example of how a cell regulates ATP production by negative feedback and Allosteric inhibition. |
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Term
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Definition
| Located near the nucleus and are flattened membranous sacs surrounded by vesicles. Packages and secretes substances made by the rough ER. |
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Term
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Definition
| A theory that organisms that descend from a common ancestor gradually over a long period of time, in a linear or branching fashion. However, not supported by fossil record. |
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Term
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Definition
| The father of modern genetics and an Austrian monk who, in the 1850s, discovered the principles of inheritance by breeding generations of garden peas. He was also important because he brought an experimental and quantitive approach to the study of inheritance. First, he studied clear-cut traits. Second, he used large samples. Third, he applied statistical analysis to his data. |
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Term
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Definition
| Discvered that some bacteria can transform harmless cells in pathogenic cells through the transferring of a genetic agent from one bacteria cell to another. This is called bacterial transformation. |
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Term
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Definition
| Electrons that are found in the lowest available energy state, and so the atom is said to be in a ground state. |
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Term
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Definition
| Ground tissue is by far the most common and “least” specialized of plant tissue. They function mainly in storage, support, and photosynthesis. Ground Tissue consists of three cell types: sclerenchyma, parenchyma, and collenchyma. Parenchyma cells have thin and flexible primary cell walls and no secondary walls, and a protoplasm with a single large vacuole; they function in metabolic processes. Many of these cells retain the ability to differentiate into other types of plant cells later on in their life; for example, when the plant is injured. Collenchyma cells have unevenly thick primary cell walls, reinforced by lignin, and lack secondary cells walls. They are alive at functional maturity and support the growing areas of a plant, especially the stems. Sclerenchyma cells have very thick primary and secondary cell walls reinforced by lignin; they support the plant. They are dead at functional maturity, and there are two types: fibers and sclereids. Fibers are long and thin, and usually occur in bundles. Sclereids are short and have irregular shapes; they make up tough seeds coats. |
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Definition
| External signals stimulated by other cells that can stop or intiate cell division. |
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Definition
| R-strategists reproduce rapidly when the environment is uncrowned and the resources are vast, that is, they are opportunistic. K-strategists are other species that operate at a density near the carrying capacity (k) of the environment they live in. |
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Definition
The first seed plants to appear. The seeds exposed on modified leaves that form cones. Conifers rapidly became a dominant life form because they were better suited to hot and arid environments than most ferns. The following are some modifications for dry environments:
- needle-shaped leaves, which have a thick cloak of cuticle (prevents water loss)
- the leaves have a relatively small surface area, preventing water loss
- Examples include pines, firs, redwoods, junipers, and sequoia |
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Definition
| AIDS stands for acquired immune deficiency disease. Those suffering from AIDS often have wrecked immune systems, and are highly susceptible to opportunistic diseases, infections, and cancers. HIV is the actual virus (AIDS is a stage of that virus’ progression). HIV targets and destroys cells that bear CD4 molecules on their cell surfaces, meaning helper T cells. Obviously, this prevents the more powerful aspects of the immune system from being activated. HIV uses reverse transcriptase, and integrates the newly formed DNA into the host cell genome. There it remains. |
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Definition
| a form of sympatric isolation in which two organisms live in the same area but enocunter each other only rarely. |
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Definition
| One of the simplest forms of learning, in which an animal ignores some persistent or constant stimulus because that stimulus has never resulted in some negative result for the animal. |
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Definition
| The rate at which the radioisotope decays eventually leads it to diminish. This rate of decay is called the half-life. |
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Definition
Enables us to calculate frequencies of alleles in a population. The letter p stands for the dominant allele in a locus with only two forms and q stands for the recessive allele. The equation is as follows:
p2 + 2pq + q2 = 1 OR p + q = 1 |
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Definition
| An enzyme that unwinds the double helix at the replication fork. |
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Definition
| A respiratory pigment attached to red blood cells that can carry up to four molecules of oxygen. Hemoglobin is an Allosteric molecule said to exhibit cooperativity. This means that once hemoglobin binds to a single oxygen molecule, it undergoes a conformational change that allows it to more easily bind to another three molecules. Hemoglobin is also sensitive to pH. The Bohr Shift idea describes the drop in hemoglobin’s affinity towards oxygen in response to a drop in pH. Graphs showing this follow a simple rule: the farther to the right the curve is, the less affinity hemoglobin has for oxygen. |
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Definition
| Sex-linked Recessive; abscene of proteins needed for blood clotting. |
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Definition
| Carried out experiments lending strong indirect experimental evidence that DNA is the genetic material. They achieived this by tagging bacteriophages with radioactive isotopes. They then tracked both inserted proteins and DNA, and found that DNA from the viral nucleus, and not proteins from the external protein coat, are resposible for infecting bacteria. |
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Definition
| Preserves multiple alleles in a population. A phenomena in which the hybrid individual is selected for since it has far greater reproductive success. For example, individuals heterozygous for Sickle-cell anemia (Ss) do not express the trait, but are also granted a natural resistance to malaria. |
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Term
| Historical Context for Evolution |
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Definition
| Aristotle summarizes the view of the Ancient World in his ordering of all known creatures on a locked scale of complexity. Linnaeus specialized in taxonomy, and believed the organization of classification would reveal a divine plan at work in nature. He developed the system used today: binomial nomenclature. Cuvier studied fossils and discovered that a series of catastrophes was responsible for the dispersal of organisms; he was a strong opponent of evolution. James Hutton published the theory of gradualism in 1795, and stated that the earth had been shaped by slow gradual change. Lyell was a leading geologist who stated that geological change results from slow, continous actions. Lamarck developed a theory of evolution around the same time as Darwin, and his theory relies on the ideas of inheritance of acquired characteristics and use and disuse. He stated that individual organisms change in response to their environment. Wallace published an essay describing a theory of natural selection identical to Darwin’s. Finally, Darwin was a naturalist who, upon visiting the Galapagos Islands, worked out the mechanism of natural selection. |
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Definition
| Produced in the ductless endocrine glands and move through the blood to a specific target cell, tissue, or organ. They produce an immediate, short-lived response. Tropic Hormones are those with an amplified effect because they trigger other glands to release other hormones. Examples of hormones include adrenaline, epinephrine, and ecdysone (controls insect metamorphosis). Examples of Tropic Hormones are TSH, which stimulates the thyroid to release thyroxin. Pheromones in dog urine carry messages between different dogs; nitric oxide gas diffuses to and affects other cells before being broken down. |
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Definition
| The range of organisms that a virus can attack. |
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Definition
| The digestive system has two important functions: digestion and absorption. Everything gets broken down into their constituent parts during the process, and absorbed by the tract itself. The tract is about 30ft long and is made of smooth involuntary muscle that, through a process called peristalsis, pushes food along the tract. The mouth is where mechanical digestion occurs. The tongue and differently shaped teeth work in tandem to grind up food. Chemical digestion also begins in the mouth, as saliva released by the salivary glands begins the breakdown of starches. After swallowing, food travels to the esophagus, directed there by a flap of cartilaginous tissue called the epiglottis, which shields the windpipe. The food then travels to the stomach. The stomach, through strong rhythmic contractions, continues to break down food mechanically. Gastric juice, a chemical cocktail of the enzyme Pepsinogen and hydrochloric acid, is also secreted by chief cells. This creates a highly acidic environment (about pH 2-3) that kills many pathogens in the food. The Cardiac Sphincter keeps the acid from traveling up into the pharynx, because doing so can causes ulcers to form, because the esophagus does not have many of the adaptations of the stomach to deal with the high acidity. The stomach secretes a thick layer of mucus (which is highly basic) over itself to counter-act the actions of gastric juice, and in addition, has thick muscular walls. Digestion is completed in the duodenum, or the first 12 inches or so of the small intestine. Bile, produced in the liver but stored in the gallbladder, acts as an emulsifier to isolate and facilitate the hydrolysis of fats. Trypsin and Chemotrypsin, both peptidases, continue to break down proteins. Lipases hydrolyze lipids, and nucleases nucleic acids. The food, now a thick paste, moves to the lower part of the small intestine. This is the site of absorption. Millions of tiny projections called villi, which are in turn covered by more projections called microvilli, greatly increase the surface area to something comparable to a tennis court. Each villus contains capillaries, which absorb amino acids, vitamins, and Monosaccharides; and lacteals, which absorb fatty acids and glycerol. The epithelial cells form a semi-permeable layer around the villi. The large intestine or colon serves three main functions: the removal of undigested waste (egestion), vitamin production, and the removal of excess water. |
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Term
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Definition
| Autosomal dominant; degenerates nervous system but shows no onset until middle age. |
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Term
| Hydrophobic and Hydrophilic Molecules |
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Definition
| Hydrophobic molecules are said to be water-fearing and tend to move away from water. Hydrophilic molecules are said to be water-loving and move towards water |
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Term
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Definition
| Temporary immunity is granted to someone when antibodies from another person is transferred to the recipient. An example is IgG injections given to people with collapsed immune systems. This is also called Passive Immunity. Permanent Immunity, or Active Immunity, occurs when the person manufactures his own antibodies after falling ill and recovering, or after receiving a vaccine (or immunization). |
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Term
| Important Facts about Sex-linked Traits |
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Definition
1. Common sex-linked disorders: color blindness, hemophilia, and Duchenne muscular atrophy.
2. All daughters of affected fathers are carriers.
3. Sons cannot inherit a sex-linked trait from the father.
4. A son has a 50% of inheriting a sex-linked trait from the mother.
5. There is no carrier state for males and sex-linked traits.
6. Females have to inherit a sex-linked trait from both parents in order to express it.
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Term
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Definition
| Learning that occurs during a sensitive or critical period in the early life of an individual animal. This learning is also irreversible. Konrad Lorenz dealt greatly with this form of learning in geese. |
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Term
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Definition
| Characterized by blending. For example, a black whale is crossed with a white whale. The resultant offspring shows up as grey. The traits have blended. |
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Term
| Independent Assortment of Chromosomes |
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Definition
| Occurs during metaphase I of meiosis I. Each pair of chromosomes can line up in two possible orientations. The daughter cell receives a maternal or paternal chromosome depending on which of the two, and there is an equal 50% chance of either happening. There are about 8 million possible combinations as a result of this process. |
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Term
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Definition
| The process that starts transcription and begins when a RNA polymerase molecule binds to a promoter seqeunce. Transcription factors, proteins, then recognize a key area of the promoter sequence called the TATA box, and mediate the binds of RNA polymerase to DNA. Once RNA polymerase is bonded to the promoter sequence, transcription from the DNA template begins. |
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Term
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Definition
| Insertion is the addition of a nucleotide into the DNA sequence. A Deletion is the loss of a nucleotide in a DNA sequence. Both result in a frmaeshift, or the a shift in the entire reading order of the sequence. |
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Term
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Definition
| Consists of G1, S, and G2. The G1 phase is a period of intense growth and biochemical activity. The S phase in when the replication of DNA occurs. G2 is the phase in which the cell continues to grow and completes preparations for cellular division. MORE THAN 90% OF A CELL'S LIFE IS SPENT IN INTERPHASE. |
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Term
| Introduction of New Species |
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Definition
| The accidental introduction of hyper-successful species to new biomes has resulted in the extinctions of a large number of species: the African honeybee and the zebra mussel are two examples. |
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Term
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Definition
| The study of the interactions of organisms with their physical environment and with each other. A population is a group of individuals of one species living in one area who interact with one another. A community is formed from all the organisms living in an area. An ecosystem includes all the organisms in a given area as well as the abiotic factors with which they interact. Abiotic factors are nonliving and include temperature, water, sunlight, etc. The biosphere is the global ecosystem. |
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Term
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Definition
| Introns are long non-coding sequences cut out by snRNP enzymes and spliceosomes (small nuclear ribonucleoproteins). Exons arethe coding regions that remain. |
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Term
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Definition
| A type of mutation in which a chromosomal fragment reattaches to the orginial chromosomes in a reverse position. |
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Term
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Definition
| A form of chemical bonding in which there is a net transfer of electrons between atoms. This forms the anion, a negatively charged ion, and a cation, a positively charged ion. Ions are necessary for many vital functions. |
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Term
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Definition
| Organic compounds that differ in structure but have the same molecular formula. Geometric isomers differ in spatial arrangement around double bonds. Structural isomers differ in the covalent arrangements of their electrons. Enantiomers, or optical isomers, are mirror images of each other; however, where one enantiomer has a powerful biological effect, the other may be biologically impotent or even harmful. |
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Term
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Definition
| Atoms of one element that vary in the number of neutrons, and hence are the same electrical charge. For the purposes of chemical bonding, all the isotopes of a particular element are the same because they have the same number of electrons and valence electrons. |
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Term
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Definition
| A procedure that shows the size, number, and shape of chromosomes and can reveal the prescene of some mutations. |
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Term
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Definition
| A disc-shaped protein on the centromere that attaches the chromatid to the mitotic spindle during cell division. |
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Definition
| XXY; sterile and small male organs. |
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Term
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Definition
| Also called the Citric Acid cycle, occurs in the matrix of the mitochondrion. It requires pyruvate, the end product of the earlier process of glycolysis. Pyruvate combines with coenzyme A to form acetyl CoA. The cycle is a cyclical series of enzyme-catalyzed reactions. The conversion of pyruvate to acetyl CoA yields 1 NADH. One turn of the Krebs Cycle (a single glucose molecule can turn it twice) yields 3 NADH, 1 ATP, 1 FADH, and a byproduct, CO2. FADH and NADH go on to shuttle electrons to the electron transport chains. |
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Term
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Definition
| Codes for the regulation of three enzymes (b-galactosidase, permease, and transacetylase). If a repressor binds to the operator, RNA polymerase is prevented from binding to the promoter and transcription of structural genes is blocked. |
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Term
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Definition
| Pyruvate from glycolysis is reduced to form lactic acid, or lactate. In the process, NADH is oxidized back to NAD+. Human skeletal muscle resorts to lactic acid fermentation when not enough oxygen is present. |
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Term
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Definition
| The DNA strand replicated in a direction away from the replication fork (3' to 5') and in a series of backwards segments called Okazaki fragments. DNA ligase allows the Okazaki fragments to come together. |
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Term
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Definition
| Mendel's first law, which states that when two organisms homozygous for opposing traits are crossed, then the offspring will be hybrid and will only exhibit one of the traits, called the Dominant trait. |
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Term
| Law of Independent Assortment |
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Definition
| Applies when a cross is carried out between two individual hybrids for two or more traits that are not on the same chromosome. States that during gamete formation, the alleles of a gene for one trait segragate independently from the alleles of a gene for anither trait. |
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Term
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Definition
| Mendel's second law, which states thatduring the formation of gametes, the two traits carried by each parent seperate independently. This allows traits not observed in one generation to occur within the next generation. |
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Term
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Definition
| Refers to the strand of DNA replicated by DNA polymerases towards the replication fork (5' to 3') in a linear and unbroken fashion. |
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Term
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Definition
| A sophisticated process whereby the responses of an organism are modified by experience. The ability to learn is tied to the lifespan of the organism and the complexity of the brain. |
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Term
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Definition
| Leaves are structured to maximize sugar production and minimize water loss. The epidermis is covered by a waxy cuticle made up of cutin that conserves water. Modified epidermal cells called guard cells (which are photosynthetic) and control the opening or closing of the stomates. The inner leaf is made up of palisade and spongy mesophyll cells, which carry out photosynthesis (palisade cells are tightly packed, whereas spongy are not). Veins of vascular tissue run through the leaf and connect it to the rest of the plant. Bundle-sheath cells surround the vascular bundles and separate them from the rest of the leaf. |
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Term
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Definition
| The first main stage of photosynthesis, used to produce the ATP to drive the dark reactions. Occurs in the grana of a chloroplast. There are two possible routes for electron flow: noncyclic and cyclic photophosphorylation. Lets trace non-cyclic electron flow. First, light molecules are “caught” by the P680 photo system and antenna or accessory pigments. The electrons travel to a primary acceptor molecule and then travels down a electron transport chain, similar to the ones utilized by mitochondria during cellular respiration. This produces ATP. During the process of Photolysis, water gets split apart, providing electrons to replace those lost by photo system A in P680. The electrons travel to the P700 reaction center, part of photo system I. The electrons then travel to another primary acceptor, and then to the area carrying out Chemiosmosis, and similar to ATP production in mitochondria, relies on a proton gradient generated by the electron transport chains to phosphorylate ATP through the spontaneous movement of protons through the ATP synthase channels as a result of the proton gradient. The ATP molecules produced here are what drive the Calvin Cycle. NADP becomes reduced when it picks up two protons that were released from water in P680. The newly formed NADPH carries hydrogen to the Calvin Cycle. A difference between P700 and P680 is that the electrons that escape from chlorophyll A are replaced by electrons from photo system II, instead of electrons from water. Another difference is that this electron chain contains ferrodoxin and results in the production of NADPH instead of ATP. Cyclic Photophosphorylation occurs when the cell beings to run low on ATP; it is a short-circuited route that replenishes ATP levels. After the electrons travel to P700, they go to another electron acceptor that catapults them back to the P680 reaction center. Cyclic Photophosphorylation only yields ATP. |
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Term
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Definition
| Those factors which limit population growth. Divided into two categories: density-dependent and density-independent factors. Density-dependent factors increase directly as the population density increases. Includes competition for food, buildup of wastes, predation, and disease. Density-independent factors are those whose occurrence is unrelated to population density. These are usually natural disasters. |
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Term
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Definition
| When two genes are linked (located on the same chromosome), then they do not assort independently of each other. |
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Term
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Definition
| Genes on the same chromosome and hence are inherited together unless seperated by a cross-over event. |
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Term
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Definition
| Lipids are a diverse class of organic compounds that include fats, oils, waxes, and steroids. All of these are hydrophobic, meaning that they are not soluble in water. Structurally, most lipids follow the 1 glycerol 3 fatty acids pattern. Variety is accomplished through the different fatty acids. Glycerol is an alcohol and only exists in a single form. A fatty acid is defined as a hydrocarbon chain with a carboxyl group at one end. Saturated fatty acids are solid at room temperature, come from animals, and cause heart disease. They contain only single bonds between carbon atoms. Unsaturated fatty acids, by contrast, come from plants, are liquid at room temperature, and have at least one double bond formed by the removal of hydrogen atoms in the carbon skeleton. They hold fewer hydrogen atoms as a result. Steroids are lipids that do not have the same general structure as other lipids. They consist of four fused rings. Lipids perform the following functions: energy storage, structural, endocrine (hormones). |
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Term
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Definition
| Developed the theory of endosymbiosis. |
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Term
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Definition
| A cycle of viral reproduction; viruses replicate without destroying the host cell. The virus becomes embedded in the DNA of the host cells and remains as an inactive prophage. At some point, an environmental trigger causes the inactive prophage to enter the Lytic Phase. Viruses capable of both modes, lytic and lysogenic, are called temperate viruses. |
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Term
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Definition
| Sacs of hydrolytic enzymes surrounded by a single membrane. Principal site of intracellular digestion. Generally not found in plant cells. |
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Term
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Definition
| A cycle of viral reproduction in which the following occurs: the bacteriophage enters a cell, hijacks the cellular machinery, replicates itself many thousands of times, and then causes the hijacked cell to burst, dessimnating thousands of new phages. |
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Term
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Definition
| Crucial to recognition of self versus non-self, a collection of cell surface markers unique to every individual and have twos classes: I and II. Class I MHC markers are found on almost every body cell. Class II MHC Markers are found on specialized cells, including macrophages, B cells, and activated T cells. |
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Term
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Definition
| The equalivalent of centrosomes in plant cells. |
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Term
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Definition
| Used to map genes on a single chromosome. One unit is equal to the distance within which crossover occurs 1% of the time. |
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Term
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Definition
| Marine is the largest biome, covering over ¾ of the world’s surface. It is the most stable biome, with stable temperatures due to the high heat capacity of water and the huge volume of water itself. This biome supplies most of the food and oxygen to the rest of the world. Divided itself into different regions according to depth, sunlight, distance from shore, and open water or water bottom. |
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Term
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Definition
| A form of cell division that produces gametes with a haploid (n) chromosome number. Meiosis undergos two cycles or stages, Meiosis I and Meiosis II. |
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Term
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Definition
| A form of cell division in sex cells that results in genetically halved (n) cells; has two cycles and always produces 4 daughter cells, though in the case of egg cells, only one is feasible and the other three are not. |
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Term
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Definition
| Also called reduction division, the process by which homologous chromosomes seperate. Each chromosome pairs up precisely with its homologue into a synapsis, or a synaptonemal complex, and forms a structure called a tetrad. Synapsis is importnat for two reasons: first, it ensures each daughter cell will receive one homologue from each parent. Second, it makes possible the process of crossing-over, leading to genetic variety. |
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Term
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Definition
| The sister chromosomes seperate and a process similar to mitosis occurs, thus generating four haploid cells carrying new combinations of genes from the parent cell. |
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Term
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Definition
| Proved DNA replicates in a semi-conservative fashion. |
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Term
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Definition
| The chromosomes line up single-file on the metaphase plate in the center of the cell, and spindle fibers form, running from the centrosomes to the kinetochores in the centromeres. |
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Term
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Definition
| An important tool in studying cells. Resolution is the ability of a microscope to measure the clarity of an image. Magnification is how much an image can be zoomed in upon. Antoine van Leeuwenhoek developed the first microscope in the 1600’s. Robert Hook refined this. Light Microscopes use light, and hence can be used on living cells. Electron microscopes require a dead specimen, and use the flow of electrons through an organism to provide details. TEM are used for studying the interior of a cell. These appear flat and 2D. SEM are used to study the surface of cells and have therefore a 3D image. Phase-Contrast microscopes are used to study living, unstained cells. |
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Term
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Definition
| Carried out by DNA polymerases during replication. The proofreading and correcting of any nucleotide errors. |
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Term
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Definition
| When a point mutation transforms a codon into a stop codon, halting translation prematurely. |
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Term
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Definition
| Site of cellular respirations. Have double outer membranes and own DNA and therefore can self-replicate. |
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Term
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Definition
| The mitochondrion is enclosed by a double membrane. The outer membrane is smooth, but the inner membrane, called the cristae, is folded. The cristae divides the mitochondrion into two different compartments, the outer compartment and the mitochondrial matrix. The electron transport chains take place in the cristae membrane, the Krebs cycle in the matrix. |
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Term
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Definition
| Defined as the actual division of the nucleus. |
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Term
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Definition
| a form of cell division resulting in two genetically identical daughter cells with a chromosome number of 2n. Occurs in all somatic cells and has one cycle. |
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Term
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Definition
| States that all living things are composed of cells, cells are the basic units of all organisms, and all cells arise only from pre-existing cells. Developed from 1838-1855. |
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Term
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Definition
| A comparison of the polypeptide cytochrome c amino acid sequence, present in all cells that carry out cellular respiration, can reveal what species are closely related to what other species. |
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Term
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Definition
| Protostomes coelomates that has a soft body with a tough calcium shell, has bilateral symmetry, three distinct body zones (head-foot, visceral mass, and mantle), has a tongue-like structure called a radula, and a open circulatory system as well as gills and Nephridia. |
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Term
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Definition
| Produced by a single B cell that has been selected for a specific antigen. Important to research and in the treatment and diagnosis. |
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Term
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Definition
Characteristic Monocot Dicot
Cotyledon Number 1 2
Vascular Arrangements Scattered In a ring
Leaf Veins Parallel Netlike
Floral Parts 3’s 4’s or 5’s
Roots Fibrous Taproot |
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Term
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Definition
| There are more than two allelic variants for a gene. For example, the ABO Blood groups. A and B are codominant to each other, and O is always recessive. Therefore, six genotypes are possible: AA, AO, BB, BO, AB, and OO. |
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Term
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Definition
There are three types of muscle: smooth, cardiac, and skeletal. Smooth (involuntary) is used in to make up the walls of blood vessels and the digestive tract. It is under the control of the autonomic nervous system, and is not striated. Cardiac muscle is found in the heart and is not striated. It is self-excitable; that is, it generates it’s own action potential. Skeletal muscles are used everywhere else, are generally large and multinucleate.
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Term
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Definition
| Changes in genetic material and are the raw materials for evolutionary change. Although mutations are one locus (place) are rare, the cumulative effect of thousands of such point mutations over time has a significant impact upon a population. |
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Term
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Definition
| Any changes in the genome. Random, though can be increased by certain environmental factors. |
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Term
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Definition
| Random changes in genetic material. Occur spontaneously and randomly. Caused by mutagenic agents. If a mutation has an adverse effect on somatic or germ cells, it is referred to as a genetic disorder. Mutations are the raw material for natural selection to continue to evolve new species. |
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Term
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Definition
| A symbiotic relationship where both organisms benefit. |
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Term
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Definition
Populations tend to grow exponentially, overpopulate, and exceed available resources.
Overpopulation results in competition and a struggle for existence.
In any population, there is variation and an unequal ability of individuals to survive.
Only the best-fit individuals survive and get to pass on their traits to offspring.
Evolution occurs as advantageous traits accumulate in a population. |
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Term
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Definition
| Unsegmented worms with bilateral symmetry but little sensory apparatus. Has Protostomes pseudocoelomate, and the pseudocoelomate transports nutrients, many are parasitic, including the one that causes trichinosis from raw pork. |
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Term
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Definition
The functional unit of the kidney is the nephron. The nephron consists of a cluster of capillaries called the glomerulus. This is surrounded by a cuplike structure called the Bowman’s Capsule, and a long narrow tube called the renal tubule. About 1 million nephrons are present in each human kidney. |
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Term
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Definition
Here are random details often tested about Nephrons:
- the glomerulus is a dense network of capillaries found in the renal cortex.
- The Bowman’s Capsule encircles the glomerulus and is the site of filtration.
- The proximal tubule is the site of secretion and absorption.
- the descending loop is impermeable to salt but not to water, which increasingly moves out of the loop, therefore making the filtrate more concentrated.
- the ascending loop is impermeable to water but not to salt, which moves out.
- the distal tubule is another important part of secretion and absorption.
- The collecting duct carries the remaining filtrate through tissue with high solute concentrations. If ADH is present, the walls of the duct become permeable to water and subsequently the filtrate becomes very hypertonic. If ADH is not present, the walls remain impermeable to water. |
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Term
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Definition
| The Neuromuscular junction is the site where the axon of a motor neuron synapses to a skeletal muscle. The signal travels along the sarcolemma, having set up an action potential, and stimulates the SR to release Ca++. The muscle then contracts. |
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Term
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Definition
| Most nitrogen enters ecosystems via bacterial processes. Nitrogen-fixing bacteria live in the nodules of legume roots and convert free nitrogen to ammonium ions (NH4+). Nitrifying bacteria convert the NH4+ into nitrites and then into nitrates. These can be used by the plant. Denitrifying bacteria convert nitrates into free atmospheric nitrogen. |
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Term
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Definition
| There are four: Adenine, Guanine, Cytosine, and Thymine. A and G are called purines, and C and T are called pyrmidines. A and T bind with a double hydrogen bond, and C and G bind with a triple hydrogen bond. |
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Term
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Definition
Nitrogenous wastes are byproducts from protein metabolism. There are three nitrogenous wastes: ammonia, urea, and uric acid. The following are some general characteristics of the three:
- Ammonia: Soluble in water
Highly toxic
Generally excreted by organisms in water- -Urea:
Not as toxic as ammonia
Excreted by earthworms and humans
Formed in the liver from ammonia in most mammals
- Uric Acid: Pastelike substance that is not toxic or water soluble
Excreted by insects, many reptiles, and birds
Minimal water loss |
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Term
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Definition
| A type of mutation that occurs when homologous chromosomes failt to seperate during meiosis. |
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Term
| Nonpolar And Polar Molecules |
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Definition
| Nonpolar molecules are ins structure highly symmetrical. Polar molecules are asymmetrical. Both have important and varied uses in the biological systems of organisms |
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Term
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Definition
| Individuals choose their mates for a specific reason. This selection serves to eliminate less-fit individuals. |
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Term
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Definition
| Are either RNA or DNA molecules. These carry all the hereditary information necessary for the organism. They are made up of repeating units called nucleotides. A nucleotide, in structure, consists of a phosphate, a 5-carbon sugar, deoxyribose or ribose sugar, and a nitrogen base. A pairs with T, and C pairs with G. In RNA, A is paired with U. |
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Term
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Definition
| One or more structures inside a nucleus that contain genetic material when the cell is in interphase, and not dividing. |
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Term
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Definition
| A prominent region within the nucleus where components of ribosomes are built. |
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Term
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Definition
| Contains hereditary information in the form of chromosomes, and is surrounded by a porous semi-permeable membrane. |
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Term
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Definition
| The idea that the environment can alter or supress the activation of specific genes, such as those for intelligence. |
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Term
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Definition
| About 100 to 200 nucleotides long and are used to elongate the lagging DNA strand; joined together by DNA ligase. |
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Term
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Definition
| Also called trial and error, or pain / pleasure rewards. This is the basis of most animal training. |
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Term
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Definition
| Discovered in the bacterium E.Coli and is an important model of gene regulation. An operon is essentially a set of genes and the switches that control the expression of those gene. Jacob and Monod, whi discovered the operon in the 1940s, described two types: the inducible (Lac) operon and the repressible (tryptophan) operon. |
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Term
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Definition
| Organic compounds are simple compounds that contain carbon. There are four classes of organic compounds: carbohydrates, lipids, proteins, and nucleic acids. |
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Term
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Definition
| The sites at which DNA replication begins, where two strands of DNa unwind and seperate to form a replication bubble. |
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Term
Osmoregulation:
Excretion |
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Definition
| Excretion is the physical removal and expulsion of sometimes harmful metabolic wastes form the body of the organism. The organs of excretion in humans are the skin, lungs, kidney, and liver. |
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Term
Osmoregulation:
Freshwater Organisms |
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Definition
| The environment here is hypotonic to the organisms, and therefore these organisms constantly gain water and lose solutes. To counter this, freshwater fish excrete copious amounts of urine and uptake solutes actively. |
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Term
Osmoregulation:
Marine Invertebrates |
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Definition
| Osmoregulation is the management of the body’s water and solute concentrations. For marine vertebrates, the ocean is a strongly dehydrating environment. This is because the ocean is very hypertonic to the organisms living in it. To counteract this, many fish produce very little urine and drink large amounts of sea water. The extra salt is transported out actively. |
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Term
Osmoregulation:
Terrestrial Organisms |
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Definition
Terrestrial organisms had to evolve mechanisms and structures that enables them to eliminate metabolic wastes but at the same time retain as much water as possible. To do this, different mechanisms have evolved:
ORGANISM MECHANISM
Protista Contractile Vacuole
Planaria Flame Cells
Earthworm Nephridia
Insects Malpighian Tubules
Humans Nephrons |
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Term
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Definition
| The mating of organisms within one species that are not closely related. Maintains both strong variation and a strong gene pool. A example is found in lion hierarchy. The dominant male lion drives away the younger male lions before they become sexually mature, to prevent inbreeding. |
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Term
| Overview of Animal Behavior |
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Definition
| The study animal behavior and its’ evolutionary implications is called ethology. There are three main scientists in the field you have to know: Karl von Frisch, Konrad Lorenz, and Niko Tinbergen. Karl Von Frisch is known for his study of bee communications; Niko Tinbergen is famous for his elucidation of the Fixed Action Pattern theory; and Niko Tinbergen is known for his work with imprinting. |
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Term
| Overview of DNA to Protein |
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Definition
| The triplet code of DNA is transcribed into a codon sequence in mRNA in the nucleus. This newly formed strand of RNA is processed and edited outsdie the nucleus, and finally the codon sequence is transcribed into an amino acid sequence at the ribosomes. |
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Term
| Overview of the Food Chain |
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Definition
| The pathway along which food is transferred from one trophic or feeding level to another. Only about 10% of the energy stored in any trophic level is converted to organic matter at the level of the next trophic level. So, if you start with 1000 G of producers, the food chain can support 100 G of primary consumers, 10 G of secondary consumers, and only 1 G of tertiary consumers. This limit’s the amount of trophic levels to about 4 or possibly 5. Food chains are not isolated, one-track systems: they are interwoven with other food chains leading to food webs. |
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Term
| Overview of the Nervous System |
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Definition
The vertebrate nervous system consists of central and peripheral components:
- CNS consists of the brain and the spinal cord.
- PNS consists of all the nerves. |
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Term
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Definition
Genetic disorder; inability to break down amino acid phenylalanine. Autosomal recessive. Can be treated early in life with a special diet.
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Term
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Definition
| A symbiotic relationship where one organism, the parasite, benefits while the host is harmed. |
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Term
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Definition
| Describes two related species that have made similar evolutionary adaptations after thier divergence from a common ancestor. An example are the placental mammals of North America and the marusipial mammals of Australia. |
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Term
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Definition
| Mendel's theory of inheritance in which characteristics are carried by discrete units called genes. |
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Term
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Definition
The movement of molecules down their concentration gradient from a region of high concentration to an area of lower concentration until a point at which equilibrium is reached. Passive transport requires no active energy expenditure by the cell. Simple diffusion requires no protein channels; however, facilitated diffusion does. The protein channels used in facilitated diffusion are specific regarding what they transport. An example of simple diffusion is found in the diffusion of solutes from the blood into the Bowman’s capsule of the nephron, in the glamorous of the human kidney. Countercurrent exchange is the flow of adjacent fluids in opposite directions so as to maximize the rates of simple diffusion. This occurs in fish gills, among other places. An example of facilitated diffusion are aquaporins, specific protein channels that facilitate the diffusion of massive amounts of water across the plasma membrane. It is possible aquaporins act as gated channels that open or close in response to certain stimuli, and affecting the rate of water movement across the membrane.
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Term
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Definition
| A family tree that indicates the phenotype of one trait being studied for every member of a family. Geneticists use the pedigree to predict how a particular trait might be inherited. |
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Term
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Definition
| The frequency (in %) that individuals of a given genotype manifest at least some degree of a mutant phenotype. |
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Term
Peripheral Nervous System
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Definition
| The PNS has two main subsystems: the sensory, and motor. The Sensory system conveys information from sensory receptors or nerve endings to the central nervous system itself. The central nervous system then relays an appropriate response to the other subsystem of the sensory system, the motor. The motor subsystem itself consists of a further two divisions: the somatic and autonomic divisions. The somatic division controls the voluntary muscles. The autonomic division controls the involuntary muscles, and handles responses like the following: fight or flight response, elevated heart rate, conversion of glycogen to glucose in the liver, dilated bronchi in lung, release of vast amounts of adrenaline. All of the above are examples of the sympathetic subsystem of the autonomic division, and the following are examples of the parasympathetic subsystem: opposes the sympathetic subsystem, calms the body, decreases heart and breathing rates, enhances digestion. |
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Term
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Definition
| Convert hydrogen peroxide to water with a release of oxygen atoms by using an enzyme called catalase. |
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Term
| Pesticides and Biological Control |
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Definition
Pesticides can accumulate in humans by biological magnification and cause many problems. On the other hand, they can save lives by killing pests and increasing food production. An alternative is called biological control. The following are examples:
- crop rotations.
- introduction of natural predatory species.
- natural plant toxins not harmful to humans.
- use of insect sterilization. |
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Term
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Definition
| There are two types of phagocyte: Neutrophils and Monocytes. They moved to an infected site because they are pulled there by chemical attractants (chemo taxis). Neutrophils are short-lived cells that engulf pathogens. Monocytes are transformed into Macrophages are massive long-lived cells that engulf and destroy pathogens with combinations of Lysozyme and two toxic forms of oxygen: nitric oxide and super oxide anion. |
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Term
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Definition
| The four phases are: prophase, metaphase, anaphase, and telophase. |
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Term
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Definition
| The cell cycle consists of five major stages: G1, S, G2, Mitosis, and Cytokinesis. The first three make up interphase, which the cell spends most of its time in. G1 and G2 phases are both phases of growth and increases in cytoplasm, the S phase is the copying of DNA. Mitosis is the preparation of the cell for cytokinesis, which is the actual division of the cytoplasm. |
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Term
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Definition
| Phloem transports sucrose and solid nutrients. It always moves from source to sink, sink being where the food is needed, source being self-explanatory. This is called translocation. Mature leaves are the primary sources of sugar, although sugar may be stored in tubers, for example. Areas of growth are example of sugar sinks. Storage organs can be either sinks or source, depending on time of year. |
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Term
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Definition
| The way a plant senses the time of the year. Plants are set to a 24-hour circadian rhythm clock. Long-day plants flower when the day is longer a certain number of hours than night. Short-day plants are the reverse, and to some it does not matter, which are called day-neutral plants. Phytochrome is the photoreceptor responsible for detecting the length of day by light. |
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Term
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Definition
| A problem arising from rubisco binding to oxygen instead of carbon dioxide. This process produces no ATP and no sugar. It is therefore a deadly waste of resources to a plant. Occurs in greater frequency in warmer environments. |
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Term
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Definition
| The process by which light energy is converted to chemical bond energy and carbon is fixed into organic compounds. There are two main stages of photosynthesis: the light-dependent or light reactions, and the light-independent or dark reactions. The light reactions are used explicitly to produce ATP, which in turn drives the dark reactions, which fix energy into sugar molecules. Both reactions only occur when light is present. |
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Term
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Definition
| A plant consists of three distinct tissues, each with a different function. Dermal tissue covers and protects the plant. It includes the endodermis, epidermis, and modified cells such as guard cells, root hairs, and waxy cuticle cells. Vascular tissue consists of xylem (water transport) and phloem (sucrose and nutrient transport). Ground tissue is the most common form of plant tissue, and has many diverse functions, mainly in storage, support, and photosynthesis. There are three types of ground tissue cells. |
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Term
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Definition
| A selectively permeable membrane that regulates the passage of materials across itself. SJ Singer formulated the fluid mosaic model in 1972. The fluid mosaic model holds that the membrane act more like a liquid than a solid, is built of phosopholipid bilayer, and has various molecules embedded within it. A phosopholipid is amphipathic, meaning it has both a hydrophobic and hydrophilic region. Peripheral proteins are those proteins that are loosely bound to the surface of the membrane; integral proteins completely span the distance of the membrane. The membrane itself is stabilized by cholesterol molecules interdispersed with itself. The typical plasma membrane is about 40% lipid and 60% proteins, and so has the consistency of olive oil. Phosopholipids move along the plane of the membrane fairly rapidly. The Glycocalyx is the external carbohydrate shell surrounding the cell; it is also called the extracellular matrix. Proteins within the plasma membrane perform a wide range of functions: transport of molecules, electrons, and ions through channels, pumps, carriers, and electron transport chains. An example of a Tran membrane enzyme is adencylate cyclase, which synthesizes cyclic AMP. Receptor proteins are critical to the proper function of many complex systems. Cell to cell attachments sites are also performed by proteins: Desosomes serve as anchors for filaments and rivet cells together. |
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Term
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Definition
| A foriegn, small, circular, and self-replicating DNA molecule that inhabits a bacterium. The F plasmid was the first plasmid discovered. The F plasmid contains genes that code for cytoplasmic bridges that connect to nearby cells and allow conjugation. The R plasmid makes the cell resistant to specific antibiotics. |
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Term
| Platyhelminthes: Tapeworms |
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Definition
| Simplest animals exhibiting bilateral symmetry, an anterior end, three distinct cell layers, and a cephalization. Has true tissues and organs, a single-opening digestive tract, and are acoelomates, however, the body is very flat with a high surface area to volume ratio, and the digestive cavity is branched so that food can reach all parts of the body. |
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Term
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Definition
| The ability of a gene to affect an organism in more than a single way. In humans, an example is Marfan Syndrome, in which a single gene results in defects of the eyes, skeleton, and blood vessels. |
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Term
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Definition
| A simple form of mutation and is a single ase-pair substitution in a single nucleotide. Sickle Cell Anemia results from a point mutation. Because of the redundancy created by the wobble effect, point mutations rarely cause serious problems. |
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Term
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Definition
| Some characteristics, such as hair color and height, result from the expression of several seperate genes that vary across a continuum. This always results in a bell-shaped curve with the more extreme traits at either end. |
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Term
| Polymerase Chain Reaction (PCR) |
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Definition
Devised in 1985 and is a cell-free automated technique that can rapidly amplify or clone a piece of DNA. The target DNA is placed in a tube with Taq Polymerase (resistant to heat) with a supply of nucleotides. Some limits:
1. some information about the nucleotide sequence of the target DNA
2. the size of the target DNA must be very small
3. Contamination is a major problem. |
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Term
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Definition
| A type of mutation when a cell or organism has multiple sets of chromosomes (>2n). |
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Term
| Polyploidy (Concerning Speciation) |
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Definition
| A condition where a cell has more than two complete sets of chromosomes. Organisms that are polyploidy cannot breed with normal 2n or n organisms, and therefore are evolutionarily isolated from them. An example of sympatric speciation. |
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Term
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Definition
| Every population has a characteristic biotic potential, or the maximum rate at which a population can increase at under ideal conditions. Factors that influence this include the age at which reproduction begins, the life span during which organisms are capable of reproducing, the number of reproductive periods in the lifetime, and the number of offspring the organism is capable of producing. Certain characteristics of growth are common to all species. |
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Term
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Definition
| The following are general characteristics: they have no symmetry, are sessile (do not move and have no nerves or muscles), filter nutrients from water into a central cavity (the spongocoel), consists of two cell layers, the ectoderm and endoderm connected by the mesoglea, has no true tissues or organs, evolved from colonial organisms, and reproduce asexually as well as by fragmentation, and have no gender. They do have, however, specialized cells: Choanocytes circulate water by flagella; Spicules function in support; and Amoebocytes that function in reproduction, transport of food particles, and secretion of pre-spicules. |
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Term
| Positive Feedback in the Immune System |
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Definition
| Positive Feedback enhances an already existing process until some endpoint or maximum rate is reached. Examples include the activity of helper T cells. When helper T cells are activated, they release two cytokines, Il-1 and Il-2. Il-2 activates B cells and other T cells. Il-1, however, enhances the already existing activity of the already activated helper T cells, stimulating them until a maximum rate is reached. |
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Term
Prader-Willi Syndrome
Angelman Syndrome |
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Definition
Genomic Imprinted Disorders.
The first is several mental retardation and serious health issues.
The second is spontaneous laughter and mental problems.
The first is from the father, the second from the mother. |
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Term
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Definition
Refers to one organism eating another. Animals and plants have evolved defenses against predation. The following are defenses evolved against predation:
- plants have evolved spines and thorns and chemical poisons (strychnine, mescaline, morphine, and nicotine).
- animals use active defenses such as hiding, fleeing, or defense.
- animals also use passive defenses like the following: Aposematic coloration is the very bright coloration of poisonous animals as a warning. Batesian mimicry is copycat coloration where one harmless animal mimics the coloration of one that is poisonous. In Mullerian mimicry, two or more poisonous species resemble each other and gain an advantage due to their numbers. |
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Term
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Definition
| Embryonic tissues called meristems continually divide as a plant lives, constantly adding new growth (indeterminant growth). The Apical Meristem is located at the tips of roots and in the buds of shoots, and continually divides. Primary growth is the elongation of the plant down into the soil and up into the air. This is concentrated in the regions where the apical meristem cells are located. There are three main zones of growth: the zone of cell division or meristem layer, the zone of elongation, and the zone of differentiation. The zone of cell division is where the meristems continually divide and add new length to the plant. The zone of elongation is where those cells deposited by the zone of cell division elongate and push the zone of cell division further down into the cell or up in the air. The zone of differentiation, or specialization, is where the cells specialize according to their function. The protoderm (embryonic dermal tissue) becomes the epidermis, the ground meristem (embryonic dermal tissue) becomes the cortex (used for storage), and the procambium (embryonic vascular tissue) becomes the xylem and phloem. |
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Term
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Definition
| An enzyme that joins together RNA molecules to fashion RNA primer. |
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Term
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Definition
| Infectious proteins that can cause brain disease. It is a misfolded verison of a protein normally found in the brain. If it comes into contact with normal proteins, it causes all of them to misfold in the same way. We really have no idea what prions really are. |
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Term
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Definition
| The likelihood of some outcome. If mulitiple events occur seperately, then you multiply to obtain the propability of three happening sucessively. |
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Term
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Definition
| An earlier type of cell found in bacteria that contains no internal membranes, has circular DNA, small ribosomes, anaerobic or aerobic metabolism, an absent cytoskeleton, are mainly unicellular, and are very small (only 1 to 10 um). Example, unicellular bacteria. |
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Term
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Definition
| The nuclear membrane begins to disintegrate and the strands of the chromosomes begin to condense. The mitotic spindle begins to form, extending from one centrosome to the other. PROPHASE IS THE LONGEST PHASE OF MITOSIS. |
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Term
| Protein Theory of Inheritance |
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Definition
| Persisted until the 1940s due to a number of coinvincing factors: they are large macromolecules, they are diverse with seemingly limitless numbers of potential functions, they are a major component of all cells, and a good deal of information was known about thier structure, while almost nothing was known about DNA or nucleic acid structure. |
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Term
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Definition
| Proteins are complex macromolecules that carry out many functions. Growth and repair, cell signaling, defense against invaders, and catalyzing chemical reactions. Proteins consist of the elements S, P, C, O, H, N. Proteins can be ingested through meat, fish, poultry, and certain plants. Proteins are made of polypeptide chains consisting of units called amino acids, which are joined by peptide bonds. Dipeptides are molecules consisting of two amino acids connected by one peptide bond. Amino acids consist of a carboxyl group, a amine group, and a variable R region. There are 20 amino acids; 10 can be made by the body’s cellular factories, and 10 must be ingested through food. All 20 are needed for the assembly of proteins. Protein function is determined by structure; each has a specific shape. Proteins have four levels of structure: primary, the unique linear sequence of amino acids; secondary, results from hydrogen bonding within the polypeptide and has two forms, an alpha helix or beta pleated sheet. Proteins that exhibit either or both at the same time are called fibrous proteins. Tertiary structure is the intricate three-dimensional shape or conformation of a protein and is what largely determines the specific function of the protein. Quaternary structure refers to proteins that consist of multiple polypeptide chains. An example of this is hemoglobin, which is built of four polypeptide chains. The protein folding problem is a question about how proteins assume shape. It appears other chaperone proteins are intimately involved in the process. |
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Term
| Protostomes and Deurostomes |
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Definition
| The two categories of coelomates. Protostomes have the first opening (the blastopore) develop into the mouth. Deuterostomes have the second opening become the mouth and the blastopore develop into the anus. |
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Term
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Definition
| The new theory of evolution replacing gradualism that states that new species suddenly appear after long periods of relative stasis. |
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Term
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Definition
| A single-stranded helix consisting of repeating nucleotides: A, C, G, and uracil (u), replacing thymine. THe 5-carbon sugar in RNA is replaced with ribose. |
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Term
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Definition
| A molecule used to prime or prepare a new DNA strand for elongation by DNA polymerases, which cannot initiate DNA replication. Joined RNA molecules by primase enzymes. |
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Term
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Definition
| A series of enzymes alter a newly formed mRNA strand by cutting out long non-coding sequences called introns. A 5' end cap conssiting of G is added to the 5' end. A poly (A) tail of A is added to the 3' end. This protects the ends of the mRNA molecule from degradation. |
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Term
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Definition
| Some isotopes are unstable, meaning they give off energy in the form of radiation. They have many practical applications, such as being used as molecular tracers, measure the age of fossils, or in some cases, detect and treat certain diseases. However, they can change the genetics of a still-living organism and its future offspring. |
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Term
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Definition
| One human ovum and one sperm each represent 8 million different possibilities of chromosome combinations. Thus, 64 million different combinations are possible. |
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Term
| Ratio of Volume to Surface Area |
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Definition
| Controls the growth and division of a cell in the cell cycle, and determines how fast the cell can take up nutrients needed for metabolism and dispose of wastes from those same metabolic processes. |
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Term
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Definition
| DNA that has been combined from two different sources. Recombinant DNA used for practical purposes by scientists is called biotechnology or genetic engineering. |
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Term
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Definition
| The simplest nerve response, and is inborn, automatic, and protective. The knee-jerk reflex is an example. This type of response allows a part of the organism, such as a hand, to be moved away from danger faster than the brain figures out what has occurred. This allows such responses to be far quicker. |
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Term
| Regulation of Gas Exchange in Humans |
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Definition
| The respiratory system is regulated in humans by the medulla in the brain. The medulla sets the rhythm in the brain by monitoring carbon dioxide levels in the blood through sensing fluctuations in the pH of the blood, which is normally at 7.4. Carbon Dioxide dissolves in the blood to form carbonic acid. The higher the carbon dioxide concentration, the lower the pH. A pH lower than 7.4 will increase breathing, and a pH over 7.4 will decrease it. |
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Term
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Definition
| The kidney is able to quickly respond to the changing requirements of the body because it is under the control of the nervous and endocrine systems. ADH is a hormone which regulates the behavior of the kidneys: it is produced in the hypothalamus region of the brain, and is stored and released by the posterior pituitary. It targets the collecting duct of the nephron. If the salt concentration is too high, ADH is released into the blood. It increases the permeability of the collecting tubule to water so that more water can be reabsorbed back into the body and urine volume is reduced. Alcohol blocks the release of ADH, and therefore results in increased urination and even dehydration. This is all linked to a feedback mechanism that maintains homeostasis. |
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Term
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Definition
| Formed by the separation of two DNA strands at the origins of replication; thousands may be present along the length of the molecule to hasten the overall process. These also expand as replication proceeds in both directions, and have a Y-shaped region called a replication fork at each end. |
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Term
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Definition
| A Y-shaped region formed by expanding replication bubbles where the new strands of DNa are elongating. |
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Term
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Definition
| one group of genes within a population becomes seperate from another group of genes in another population, and no interbreeding between the two populations can occur. |
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Term
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Definition
| A sympatric speciation in which closely reltaed species may be barred from mating due to differences in anatomy, prezygotic barriers, or postzygotic barriers. |
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Term
| Resting Potential of Nervous cells |
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Definition
| All living cells exhibit a membrane potential, or a electrical difference in charge between the cytoplasm, and the extracellular fluid. A neuron in an unstimulated or polarized state is about -70 mV. This is maintained through the actions of the sodium potassium pump that actively pumps ions across the membrane. For the nerve to transmit a signal, the signal itself must be greater than the resting potential or resting threshold of the cell; the larger the membrane potential, the stronger stimulus is needed to cause the nerve to fire. |
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Term
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Definition
| A form of transduction that involves the transfer of specific DNA from the host cell to the phage. |
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Term
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Definition
| Discovered in the late 1960s and are extracted from bacteria in extreme environments. Cut DNA at specific recognition sequences, often leaving staggered sticky ends and restriction fragments. |
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Term
| Restriction Fragment Length Polymorphisms (RFLPs) |
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Definition
| When scientists compared noncoding regions of DNA, they found highly variable regions; an analysis of this region provides a human fingerprint. RFLPs are unique, and inherited in a Mendelian fashion. RFLP analysis results in a high degree of certainty. |
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Term
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Definition
| Viruses that contain RNA instead of DNA and replicate in an unusual way. The RNA, following the infection of the host cell, serves as a template for the synthesis of cDNA. The retroviruses thus reverse the flow of information from DNA to RNA. Occurs under the direction of reverse transcriptase. |
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Term
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Definition
| The enzyme that controls reverse transcription in retroviruses. |
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Term
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Definition
| Another antigen located on the surface of RBC. 85% of the world population has the antigen and are said to be Rh+. The other 15% are called Rh-. |
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Term
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Definition
| Site of protein synthesis. Either attached to the endoplasmic reticulum or found free-floating in the cytosol. |
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Term
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Definition
| Roots absorb nutrients from the soil, like water and minerals, anchor the plant to the ground, and store food in tubers. The epidermis covers the entire surface of the root and is modified for absorption. Root hairs greatly increase the surface area of the total root. The cortex consists of parenchyma cells that store starches. The stele, or vascular cylinder, consists of vascular tissue surrounded by the pericycle, a region of lateral meristems from which secondary growth may arise. The Endoderm is a tightly packed layer of cells wrapped with the Casparian strip, a continous band of suberin, a waxy substance impervious to water and dissolved minerals. The endoderm therefore functions in selecting what substances can enter or leave the stele. |
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Term
Rosalind Franklin
1950 - 1953 |
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Definition
| Carried out x-ray crystallography analysis of DNA in Maurice Wilkins' London lab, and found DNA's structure to be helical. Her work proved critical to Watson and Crick, but however she did not share a Nobel prize as she had died and the prize is not awarded posthumously. |
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Term
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Definition
| A hormone produced in the salivary glands and that breaks down starches |
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Term
| Scientists who think about the origin of life |
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Definition
| AI Oparin and JBS Haldane think seperately that organic molecules could have arisen from the conditions of early earth. Stanley Miller and Harold Urey proved almost any energy source could have powered organic molecules. Sidney Fox, more recently, carried similar examples and produced short-lived cell-like structures. |
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Term
| Second Line of Nonspecific Defenses |
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Definition
This line is meant to limit the spread of invaders in advance of more complex immune responses. It includes the following:
- Inflammatory response: histamine triggers vasidilation, which brings more WBC to the area. Histamine is secreted by basophil cells and mast cells; also responsible for symptoms of the common cold.
- Prostaglandins further divert blood flow to the area.
- Chemokines secreted by the blood vessel endothelium and Monocytes attract more WBC to the area.
- Pyrogens, released by certain WBC, increase body temperature to hasten.
- Phagocytes ingest invading microbes. Phagocytes will be discussed later.
- Complement, an array of activated proteins, attacks pathogens.
- Interferons inhibit viral reproduction.
- Natural Killer (NK) Cells puncture cell membranes of destructive cells, including pathogens and cancer cells, causing water in flood in through a process called lysis. |
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Term
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Definition
| Secondary growth is the elongation of the plant to the sides, and is carried out by lateral meristem cells. This gradually thickens the plant in girth. |
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Term
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Definition
| A hormone involved in human digestion and that stimulates release of buffers. Produced in the Duodenum. |
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Term
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Definition
| Seed plants, in contrast, are heterosporous, meaning that they produce two kinds of spores, megaspores and microspores. Megaspores develop into female gametes, while microspores develop into male gametes. There are two types of seed plants: gymnosperms (cones) and angiosperms (flowers). |
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Term
| Semi-Conservative Replication |
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Definition
| The mechanism for eukaryotic DNA replication predicted by Watson and Crick in which the double helix unwinds and each strand serves as a template for the formation of a new strand composed of complementary nucleotides. The two new molecules each have one new strand and a single old strand. c |
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Term
| Sequence of Energy Flow During Respiration |
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Definition
| Glucose-----Glycolysis----Krebs Cycle-----FAD and NAD-----ETC-----Chemiosmosis-----ATP. |
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Term
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Definition
| Traits carried on the X and Y chromosomes. Note, may not be coding for gender but for something else. These genes are said to be sex-linked. As a result of this, a male (XY) has only to inhiert one copy of a recessive sex-linked disorder in order to express it, while a female has to inherit two copies (XX). |
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Term
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Definition
| Those traits whose expression differ between the sexes. An example is baldness. |
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Term
| Sexual Reproduction (Angiosperms) |
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Definition
| The flower is the main sexual organ of a plant. Pollen grains come down pollen tubes into the ovaries, where fertilization occurs. One sperm nucleus fertilizes the egg and becomes the zygote (2n). Another sperm nucleus fertilizes the two polar bodies and becomes the triploid endosperm (3n), which is food for the developing embryo. This is called double fertilization. After, the ovule becomes the seed and the ovary the fruit. The seed is built of a protective seed coat, the embryo, and the cotyledon or endosperm. The embryo itself consists of the hypocotyls (lower part), the epicotyl (upper part), and the radicle (embryonic root). The seed gets buried in the ground and grows. The main advantages of sexual reproduction are genetic variety and adaptation, and dispersal of seeds over a wide area. |
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Term
| Sexual Reproduction, in terms of evolutionary variation |
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Definition
| Provides variation due to the shuffling and recombination of alleles during meiosis and fertilization. The independent assortment of chromosomes during METAPHASE I results in the recombination of unlinked genes. Crossing over occurs during MEIOSIS I and combines genes from different chromosomes. The Random fertilization of one ovum by one sperm results in enormous variety. |
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Term
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Definition
| Selection based on variation in secondary sexual characteristics related to the attraction and competition for mates. Sexual dimorphism is the differences in appearance between the males and females populations of the same species due to the actions of sexual selection. |
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Term
| Single-Stranded Binding Proteins |
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Definition
| Proteins that act as scaffolding to hold two DNA strands apart. |
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Term
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Definition
| Refers to the two genetically identical halves of a replicated chromosome. |
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Term
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Definition
| The total number of individuals in a population and represented by N. |
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Term
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Definition
| Myofibrils are fibers that run parallel to the length of the cell. They consist of thick and thin filaments. Each thin filament is built of two chains of actin proteins. Each thick filament is composed of two long chains of myosin molecules, each having a globular head. The concentration of sacromere depends on two other molecules: troponin and tropomyosin, in addition to Ca++ ions. As cross-bridges that form between trosponin and tropomyosin break and reform again, the muscle contracts. |
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Term
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Definition
| In some instances of reproductive isolation, even if the two populations do come back together and have the potential to reproduce, it may no longer be anatomically possible. The emergence of a new species is said to have occured. Speciation results from anything that can fragment two populations and isolate small groups of individuals. There are three main forms: allopatric speciation, sympatric speciation, and polyploidy. |
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Term
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Definition
| A population whose members have the potential to interbreed in the wild and produce viable offspring. |
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Term
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Definition
| The third line of defense is specific and consists of lymphocytes. There are two types of lymphocytes: B and T. Both recognize different specific antigens (substances which trigger antibodies) and circulate in the blood and lymph. B lymphocytes mature in the bone marrow and launch a humoral response, involving the production of antibodies. They are stimulated by either T lymphocytes or antigen presentation, and once activated, are estimated to secrete almost 2,000 antibodies a second. T lymphocytes mature in the thymus gland and utilize what is called a cell-mediated response. They are stimulated by either infected body cells or antigen-presenting cells (APC’s), and themselves activate B lymphocyte differentiation. There are two main types of T lymphocytes: cytotoxic T cells and helper T cells. Cytotoxic T cells kill infected body cells or pathogens or cancer cells. They have receptors that bind to Class I MHC molecules. Once it binds to a class I MHC marker, a CD8 surface protein holds the two together until the cytotoxic T cell is activated. Cytotoxic T cells differentiate into either plasma cells or memory cells. Activated Cytotoxic T cells release perforin which causes pores to form in the membrane, and the target cell then lyses and dies. Helper T cells alert the immune system to the presence of pathogens in the body. They have surface receptors that bind to Class II MHC molecules. Note: if an activated T cell binds to a body cell displaying an incorrect MHC marker, then it will attack. A CD4 surface protein holds the two together until the helper T cell is activated, thereupon proliferating and differentiating into plasma and memory cells. Helper T cells stimulate cytotoxic T cells, B cells, and other helper T cells by releasing the cytokines, interleukin-1, and interleukin-2. |
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Term
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Definition
| Eliminates the extreme phenotypes of a population and favors the more moderate expressions. In humans, stabilizing selection keeps the majority of birth weights in the 6 to 8 pounds range. |
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Term
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Definition
| Stems connect the photosynthetic leaves to the rest of the non-photosynthetic plant. Vascular Bundles are strands of vascular tissue running the length of the stem (Xylem-inside, Phloem-outside, meristem-middle). Monocot vascular bundles are scattered, dicot vascular bundles are arranged into a symmetrical ring. The ground tissue consists of cortex and pith, both modified for storage. Apical meristem is located at the tip and allows the plant to grow. Lateral meristem located at the sides replaces the epidermis with a tough layer of dermal tissue (bark). Again, wood is secondary xylem accumulated over the years. Get that in your head now. |
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Term
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Definition
Openings that absorb crucial carbon dioxide and other gases, but at a cost of losing great amounts of water. Guard Cells control the opening and closing of the stomates by their conformation. When the guard cells become turgid (water flows in), the stomates open; when the guard cells become flaccid (water flows out), the stomates close. The following will cause the stomates to open:
- depletion of carbon dioxide in the air spaces of the leaf.
- increase of potassium ions in guard cells, which causes water to flow in.
- stimulation of a blue-light receptor in guard cells, causing the uptake of K+ ions.
- active transport of H+ ions from the guard cells.
The following will cause the stomates to close:
- lack of water, causing the guard cells to become flaccid.
- high temperatures, by increasing carbon dioxide levels in the air spaces of a leaf.
- Abscisic Acid, produced in the mesophyll in response to dehydration.
- a decrease in K+ ions in the guard cells, causing water to flow out, closing it. |
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Term
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Definition
A twitch is when a single action potential causes a muscle to contract locally. A summation effect is when a second signal arrives before the first is over. Tetanus is one smooth sustained contraction caused by overlapping summation effects (it is not related to the disease). Eventually, the muscle will fatigue and relax.
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Term
| Survivorship Curves in Populations |
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Definition
| Shows the size and composition of a population; there are three types. Type 1 shows organisms with low death rates in young and higher rates in old age. It is characteristic of human populations. Type 2 shows a species with a high death rate throughout all the stages of life. Type 3 shows a very high death rate among the young but then shows that death rates decline for those who live past a certain age. |
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Term
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Definition
| Speciation due to non-geographical factors; examples are polyploidy, habitat isolation, behaviorial isolation, temporal isolation, reproductive isolation. |
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Term
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Definition
Located in northern Canada and Russia. Dominated by conifer forests, like spruce and fir. Marked by extremely cold winters, and forms the largest terrestrial biome. Has great snowfall; typical animals include moose, black bear, lynx, elk, wolverines, martens, and porcupines.
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Term
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Definition
| A single, large root that gives rise to lateral branch roots. Taproots store water deep in the soil. Taproots of certain species may be modified for storage of food, like starches. |
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Term
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Definition
| Autosomal recessive. Inability to break down lipids in brain. Common in Ashkenazi Jews. |
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Term
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Definition
| Enzymes that construct and maintain telomeres. |
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Term
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Definition
| Each time DNA replicates, somenucleotides at the farthest ends are lost, usually from noncoding regions. To help prevent this, these are protective shields that repeat nonconsequential sequences thousands of times. Created and maintained through the actions of telomerases. |
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Term
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Definition
| The chromosomes cluster at opposite ends of the cell, and the nuclear membrane reforms. The supercoiled chromosomes begin to return to thier normal state. |
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Term
| Temperate Decidous Forests Biome |
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Definition
| Found in the northeast of North America, and characterized by the presence of trees that drop their leaves during winter. Rich soil. Moderate temperatures during all seasons. Examples include looking outside the window. |
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Term
| Temperate Grassland Biomes |
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Definition
| Covers huge areas across the globe. Characterized by low total rainfall, meaning there are little forests. Examples include American prairie or African savannah. |
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Term
| Temperature Regulation in Endoderms |
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Definition
| Endotherms actively regulate their internal temperature by a vast expenditure of energy. They maintain a constant body temperature despite external fluctuations, and many maintain this temperature much higher than their surroundings. In humans, as much as 60% of nutritional intake goes towards regulating temperature. The metabolic rate of a mammal, therefore, is roughly ten times that of a similarly sized reptile (which is ectothermic). Mammals pay this price by remaining active for longer (a benefit conferred by endothermy), and by evolving highly efficient and complex digestive systems that absorb the most of their food. A long, convoluted alimentary canal and a huge number of villi and microvilli facilitate uptake of nutrients. Birds have an even higher metabolic requirement. Birds that fly must eat at least 30% of their body weight a day. |
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Term
| Temperature Regulation in Poikilotherms |
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Definition
| Most aquatic animals (not including aquatic mammals, like whales) maintain a body temperature that is the same as the surrounding water. These animals, like fish, regulate their temperature passively by moving to areas of warmer or colder water as need be. This is an example of ectothermy, or the passive regulation of internal temperature. |
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Term
Temperature Regulation:
The mechanism of Countercurrent Exchange |
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Definition
| Helps to warm or cool extremities, such as your fingers and toes. Warm blood flows parallel to cold blood, thus warming it and vice versa. It is important to remember that countercurrent exchange can also help to cool the body as well as warm it. |
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Term
| Temperature Regulation: Problems of living on land |
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Definition
Temperatures on land, compared to temperatures in the sea, fluctuate constantly and enormously. A north-south cline is an anatomical difference evolved due to geographical climate. A example are the ears of a jackrabbit. Animals maintain a more or less constant temperature through several behavioral adaptations:
- snakes warm themselves in the sun.
- animals huddle to conserve heat on a cold prairie.
- dogs pant to cool themselves.
- humans shiver, jump around, and turn on the heating to stay warm. |
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Term
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Definition
| A sympatric speciation in which reproduction becomes available at different times. |
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Term
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Definition
| When RNA polymerase binds to a termination sequence, it is subsequently cut free from the template DNA strand and transcription is complete. |
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Term
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Definition
A territory is an area which an organism defends and from which other members of the same species or which use the same resources are excluded. The size varies with the resources and requirements of the animal.
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Term
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Definition
| A way to determine if an individual plant or animal exhibiting a certain trait is BB or Bb. This is determined by the genotypes of the offspring. |
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Term
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Definition
| Located beneath the sternum and the size of a clenched fist. The heart beats about 70 times a minute and pumps about 5 quarts of blood per minute, or the total volume of blood in a adult human. Two atria receive blood, and two ventricles pump it back out. Cardiac muscles cells are self-excitable. The heart itself has its’ own innate pacemaker, the SA node, which generates and sends electrical signals to the AV node, which in turn delays it for less than a second, and then releases it. Electron cardio grams detect these signals. The SA node is regulated by a number of factors: two sets of nerves than can quicken or slow down, hormones such as adrenaline, and body temperature. Blood pressure for normal, resting adults is 120 / 80. The 120 corresponds to the systolic (contraction) phase of the heartbeat, while the 80 corresponds to the diastolic (relaxation) phase of the heartbeat. |
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Term
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Definition
| Consists of 3 Billion base pairs of DNA and about 30, 000 genes. 97% of human DNA does not code for protein product (junk). Of the noncoding DNA, most are regulatory genes, some are introns, and most are never coded. Polymorphic regions of DNA are those regions that are highly variable among individuals. |
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Term
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Definition
| The part of the brain that acts as a bridge between the endocrine and nervous systems. Acts as part of the nervous system by sending electrical shocks to the adrenaline gland to release adrenaline; acts as part of the endocrine system when it produces oxytocin and ADH. The hypothalamus contains the “Thermostat” of the body and functions as a regulations center for hunger and thirst. |
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Term
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Definition
| The human kidney functions as both an osmoregulatory and excretion organ. Human kidneys require large amounts of blood, and is supplied by the renal artery and the renal vein. The kidneys filter about 1000 - 2000 liters of blood a day, and produce on average about 1.5 liters of urine. If fluid intake is high and salt intake is low, then the kidney will produce dilute urine in copious amounts. The reverse is also true. The function unit of the kidney is called the nephron, and will be covered next. |
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Term
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Definition
A cell body, containing a nucleus and other organelles, and two possible cytoplasmic extensions called dendrites or axons. Dendrites are sensory: they receive messages from other cells and carry the electrical signal to the cell body. Hundreds are present. There is only a single axon, but it can be much longer (up to several feet in a giraffe); Axons transmit signals to other cells. There are three types of neurons:
1. Sensory neurons receive an initial stimulus from a sense organ, such as the eyes.
2. Motor neurons stimulate effectors to produce a response to a signal.
3. Association neurons reside within the spinal cord and brain, receive signals, and transfer the information to a motor neuron, or possibly to the brain for further processing. |
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Term
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Definition
| Used when more than one arrangement of the events factoring into the outcome is possible, then the individual chances are added. |
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Term
| The Rule of Multiplication |
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Definition
| Used to find the chances of two independent events (do not affect each other) happening. To do this, you mutliply the chance of one occuring by the chance of the other occuring. |
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Term
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Definition
| Signals cross a synapse chemically. The cytoplasm at the terminal branch of the presynaptic neuron contains many vesicles, each containing thousands of molecules of neurotransmitters. Depolarization causes the Ca2++ ions to rush through calcium-gated ion channels. This sudden rise causes the vesicles to with the presynaptic membrane and release the neurotransmitters by Exocytosis. There, the neurotransmitters bond with receptors on the post-synaptic side, thus altering the membrane potential of the postsynaptic cell. Depending on the types of receptors and the channels they control, the cell will be either inhibited or stimulated. An enzyme called Esterase then destroys the neurotransmitter. Serotonin and epinephrine are two examples of neurotransmitters. Nitric oxide gas can also act as a neurotransmitter. |
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Term
| The Technique of Gene Cloning |
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Definition
1. Isolate a gene of interest
2. insert the gene into the plasmid
3. insert the plasmid into a vector
4. clone the gene.
5. identify the bacteria that contains the selected gene. |
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Term
| The steps of osmoregulation in the human body |
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Definition
| There are four major steps: filtration, secretion, reabsorption, and excretion. Filtration occurs as blood pressure forces fluid from the blood into the glomerulus inside of the Bowman’s capsule. Podocytes and slit pores are modified cells that increase the rate of filtration. Filtration occurs by diffusion and is passive and nonselective. Some solutes diffuse out here. From the bowman’s capsule, the filtrate travels to the proximal tubule, then down the loop of Henle, to the distal tubule, and then to the collecting duct. From there, it is temporarily stored until excreted. The picture below maps the travel of the filtrate through the nephron. Secretion is the active, selective uptake of molecules that do not get transferred into the Bowman’s capsule. This occurs in the proximal and distal tubules. Reabsorption is the process by which most of the water and the solutes are transported back to the peritubular capillaries and then back to the rest of the body. This begins in the proximal tubule and continues to the collecting duct. The loop of Henle acts as a countercurrent exchange mechanism. The longer the loop, the greater the absorption of water. Excretion is the removal of metabolic wastes. Everything that passes into the collecting duct is excreted from the body. |
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Term
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Definition
| A theory concerning the emergence of eukaryotic cells that states that eukaryotes emerged when mitochondria and chloroplasts, once autonomous prokaryotes, took up residence in larger prokaryotes. Over time (about 1.5 billion years), the characteristics typical of a eukaryotic cell emerged. |
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Term
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Definition
| The method of DNA replication used by bacteria that travels in both directions from a single point of origin. |
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Term
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Definition
| A system used instead of the 6 Kingdoms system based on DNA analysis. It has three broad distinctions: Bacteria, Archaea, and Eukarya. Bacteria includes prokaryotes such as cyanobacteria and gram positive bacteria; Archaea include prokaryotes like extremophiles and halophiles, and Eukarya includes eukaryotes like protists, fungi, plants, and animals. |
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Term
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Definition
| Used to study the properties of specific cells in vitro. Usually, the desire is to gain knowledge of the life cycle of cells. |
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Term
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Definition
| Toxins used in industry have found their way into the food webs. Any carcinogens or teratogens in commercial livestock used for food, like beef, accumulated in us humans because we are at the top of every food chain, through the process of biological magnification. |
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Term
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Definition
Plants that have vascular or transport tissues. Evolved later and are today far more common than bryophytes. The following are some of the common characteristics of tracheophytes:
- xylem and phloem for transport
- lignin-reinforced transport vessels secondarily supporting the plant
- subterranean roots that take up water and anchor the plant
- leaves that increase the photosynthetic surface
- a dominant Sporophyte generation
Tracheophytes are further divided into two groups: those with seeds and those without. An example of a seedless tracheophytes are ferns. The seed plants themselves are further divided: gymnosperms (cones) and angiosperms (flowers). |
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Term
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Definition
| The process by which DNA makes RNA, specifically mRNA. Consists of three stages: intiation, elongation, and termination. Occurs inside the nucleus. |
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Term
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Definition
| Occurs in two types; and is a process whereby phage viruses acquire bits of bacterial DNA as they infect one cells after another. |
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Term
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Definition
| The process by which the codons of a mRNA sequence are changed into an amino acid sequence. Amino acids, freefloating in the cytosol, are carried by tRNA molecules to the codons of the mRNA strand at the ribosome, following the base pairing rules. A molecule called GTP provides the energy for this process. Some codons, such as AUG, are called start codons and begin translation. Others, like UAA, UGA, and UAG, are called stop codons and end translation.The process of translation has three stages: initiation, elongation, and termination. |
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Term
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Definition
| A type of mutation when a fragment of a chromosome becomes attached to another non-homologous chromosome. |
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Term
| Transport of Carbon Dioxide in the Blood |
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Definition
Hemoglobin only transports a very small amount of oxygen. Most carbon dioxide is carried in the blood plasma as part of the reversible carbonic acid-bicarbonate ion system, which maintains the blood pH at 7.4. Most carbon dioxide travels through the bloodstream as bicarbonate ions through the following reactions:
CO2 + H2O ----- H2CO3 ----- H2CO3- + H+
The reaction itself is reversible. |
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Term
| Tropical Rain Forest Biomes |
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Definition
| Generally found near the equator with abundant rainfall, stable temperatures, and high humidity. Enormously productive, i.e. account for 4% of earth’s surface but make up 20% of earth’s food production. Has the greatest diversity of any biome on earth. Dominant trees are tall and form a dense canopy. Many trees have epiphytes, or photosynthetic plants that grow on other trees. |
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Term
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Definition
| The growth of a plant towards or away form a stimuli. Could be touch, gravity, or light. Phototropisms result from an unequal distribution of auxins, on the dark side of the plant. |
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Term
Trypsin
Chemotrypsin
Pepsinogen / Pepsin |
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Definition
| Hormones; first two are produced in the pancreas, and the second in the stomach wall; involved in the breakdown of proteins. |
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Term
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Definition
| A repressible operon; continually switched on until turned off by a corepressor. When the repressor combines with a specific corepressor molecule, it changes its conformation and binds to the operator, thus preventing RNA polymerase from binding to the promoter and blocking transcription of structural genes. |
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Term
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Definition
| Located in the far northern parts of North America, Europe, and Asia. Has the permafrost, a hardened layer of frozen soil and which gets very little rainfall. Insects, and subsequently birds during certain months, are abundant. Principal animals include reindeer, caribou, arctic wolves, arctic hares, lemmings, and polar bears. |
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Term
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Definition
| Single, membrane-bound structures used for storage. Vesicles are merely tiny vacuoles. |
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Term
| Vascular Tissue in Plants |
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Definition
| Vascular tissue has two types: xylem (PASSIVE), which transports water and dissolved minerals around the plant, and phloem (ACTIVE), which transports food (sucrose) and other nutrients around the plant. Both of these processes occur passively on the part of the plant. Xylem consists of two types of elongated cells: tracheids and vessel elements. Tracheids are long, thin, and tapered and overlap; water goes from tracheid to tracheid through pits, which have no secondary cell walls, though the entire tracheid as a whole does indeed have lignin-reinforced cell walls. Tracheids, therefore, also perform a secondary function in helping to maintain the shape of the plant. Vessel elements are shorter, wider, thinner-walled, and less tapered. They are aligned end to end, but unlike tracheids, are perforated along their length, allowing water to flow freely. Xylem is what makes up wood, or bark. All the elements involved in xylem are dead at functional maturity. Phloem is the other type of vascular tissue that transports sucrose and other solid nutrients throughout the plant. The mechanisms that drive both xylem and phloem will be discussed in detail later. Phloem carries sugars from photosynthetic leaves to the rest of the plant by active transport. Chains of sieve-tube members are what make up phloem. The sieve-tube members’ ends have sieve-plates that facilitate the flow of fluid from one cell to the next. Although sieve-tube members are alive at functional maturity, they do not possess key organelles like nuclei or ribosomes; this problem is solved by the existence of companion cells that act to supplement these metabolic requirements of the sieve-tube members, also functioning in storage and therefore allowing the sieve-tube members to remain completely dedicated to their principal function of transporting sucrose from source to sink. |
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Term
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Definition
| A membrane from previous host cells cloaking a virus and capsid and aids in infecting more host cells. |
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Term
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Definition
| A parasite that dwells within another cell, and can only reproduce by hijacking a cell's cellular factories. Often, the production of tens of thousands of viruses destroys the host cell. |
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Term
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Definition
| Water evaporates from the earth, forms clouds, and rains back to the ground. Some rain penetrates the soil and goes back to the seas. Most water evaporates from plants by transpiration. |
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Term
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Definition
| Water is essential to the feasibility of life. The molecule itself is a asymmetrical and hence polar molecule. This physical characteristic is a result of the high electro negativity of the oxygen atom. One side of the atom has a positive charge and the other has a negative charge. Hydrogen bonding between adjacent water atoms is a direct result of this polar electrical charge. Consequently, the hydrogen bonds themselves are responsible for the properties of water that allow life on earth to exist. Lets list the properties of water: 1, water has a high specific heat. Specific heat is the amount of heat a substance must absorb to increase 1 gram of the substance by 1 degree Celsius. Because of water’s high specific heat, large bodies of water can act as huge reservoirs of heat, thus moderating climates in coastal regions. It can also absorb most the heat given off by the activities of metabolism. 2, water has a high heat of vaporization. Evaporation of water greatly cools an overheated body surface. 3, water is the universal solvent. It dissolves all polar and ionic substances. 4, water exhibits strong cohesion tension. This means that molecules of water tend to attract each other, which is responsible largely for the following phenomena. Water moves up a tall tree from the roots to the leaves without the active expenditure of energy on the part of the tree through what is called transpiration-pull cohesion tension. As one water molecule is pulled up, it itself pulls up another one. Capillary action results from the combined forces of cohesion (sticking together) and adhesion (sticking to other stuff). Surface tension can allow some insects and other organisms to walk on water without breaking the surface. Finally, 5, ice floats on water because it is less dense. This allows fish and other organisms to dwell below, and circulates water during the spring and summer. This cycling of nutrients in a lake is called spring overturn and is a necessary part of the ecosystem. |
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Term
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Definition
| Osmosis is the diffusion of water across the plasma membrane. Lets review those three “tonic” terms. Hypertonic is a situation in which one solution has a greater number of solutes than another solution. Hypotonic is a situation in which one solution has a lesser number of solutes than another solution. Isotonic solutions contain the same amount of solutes. Solutes always flow in a higher to lower (hyper to hypo) direction until equilibrium (iso) is reached. Water movement is looked at in terms of water potential. Water potential results from two factors: solute concentration and pressure. The water potential for pure water is zero; the addition of more solutes lowers that number to a negative value. Water will move from a solution containing a higher water potential to a solution containing a lower water potential. So, water is said to move in a direction the reverse of the solute movement above: in a hyper direction. NOTE: if a cell is isotonic to its surroundings, than water flows in and out but there is no change in the size or shape of the cell. If a cell is hypotonic to its solution, water will flow into the cell, because it has a lower water potential. The cell will swell. The cell walls of plant cells prevent the cell from bursting, however. If a cell is hypertonic to its’ surroundings, than water will flow out of the cell and it will shrink. This is called plasmolysis. |
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Term
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Definition
| Proposed the double helix structure of DNA. They dervied muc other thier information from earlier work by other scientists, such as Rosalind Franklin. Later proposed the self-replication mechanism employed by DNA. |
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Term
| X Chromosome Inactivation / Barr Body |
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Definition
| Occurs early in the development of a female child. One of the X chromosomes is inactivated in every somatic cell and occurs randomly, generating a genetic mosaic. This menas not all the cells of a female are identical. The inactivated chromosome forms a structure called the Barr Body. |
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Term
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Definition
| A technique used to determine the three-dimensional structure of a molecule. |
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Term
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Definition
Xylem transports water and dissolved minerals. Xylem fluid rises in a plant against gravity with no active expenditure of energy on the part of the plant. Root pressure pushes the liquid up and results from water flowing into the stele as a result of the high mineral content of the root cells. It can only push xylem sap a few yards, however, before it becomes too weak. Transpirational pull, on the other hand, can pull water up xylem vessels to great heights. The evaporation of water from the leaves at the top of a tree, for instance, (called transpiration) causes negative pressure to develop in the xylem tissues. The hydrogen bonds between water molecules then gives rise to two critical factors: adhesion and cohesion. Cohesion is the water molecules sticking together, allowing them to be pulled up in a column. Adhesion facilitates this by allowing the water to cling to the tissue and therefore help counteract gravity. Therefore, Transpirational pull, powered by the sun, supplements root pressure in tall plants. The following are factors affecting the rate of Transpirational pull:
- high humidity slows down pull, low humidity hastens it.
- wind increases transpiration, which increases pull.
- increased light intensity will do the same as wind.
- closing the stomates will stop Transpirational pull.
PASSIVE |
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Term
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Definition
| Carries messages in RNA form from the DNA to the cytoplasm. |
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Term
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Definition
pH is a measure of the acidity and alkalinity of a solution. Anything with a pH of less 7 is an acid, and anything with a pH of above is a base. The value of the pH is the negative log of the hydrogen ion concentration in moles per liter. Stomach acid has a pH of 2, human blood 7.4, and acid rain 1.5 to 5.4. Due to the logarithmic nature of the pH scale, even small fluctuations can be devastating, and hence the pH of most substances is maintained through the actions of buffers, such as bicarbonate ions in human blood.
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Term
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Definition
| Helps to make up the ribosome formed in the nucleolus. |
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Term
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Definition
| Shaped like a cloverleaf and carries amino acids to the mRNA at the ribosome. |
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Term
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Definition
| Another type of RNA molecule that is found free-floating in the cytosol. On one side is an amino acid molecule and the other an anticodon, which is complementary to a codon sequence in a ribosome. tRNA molecules, unlike mRNA, can be reused by the cell. Wobble is the relaxation of the basepairing rules for the third nucleotide base in the anticodon. |
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