Term
| Explain how meiosis accounts for both Mendel's law of heredity. |
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Definition
| Meiosis accounts for Mendel's law of heredity because it provides an explanation for how the recombination seen in his laws can happen. |
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Term
| What is recombinant DNA? What is it used for? |
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Definition
| Recombinant DNA (rDNA) is a form of artificial DNA that is created by combining two or more sequences that would not normally occur together.created through the introduction of relevant DNA into an existing organismal DNA, such as the plasmids of bacteria, to code for or alter different traits for a specific purpose, such as antibiotic resistance |
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Term
| Describe the regulation of genes in bacteria through a tryptophan operon. |
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Definition
| The tryptophan operon in bacteria is a “repressable operon.” It is normally transcribed, but when tryptophan is present, it binds to the trp repressor, which binds to the tryptophan operon and deactivates the operon. |
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Term
| Explain how meiosis creates variation. |
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Definition
| When the cell divides it goes down to only 23 chromosomes instead oft he usual 46 found in non-sex cells. This allows for genetic variations because genetic traits are the result of the combination of two chromosome pairs. |
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Term
| Explain how reproductive (sympatric) isolation leads to speciation. |
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Definition
| Sympatric speciation is the process through which new species evolve from a single ancestral species while inhabiting the same geographic region. |
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Term
| Explain how geographic (allopatric) isolation leads to speciation. |
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Definition
| Geographic isolation may lead to environmental differences, thus leading to an organisms different needs. These slight changes in environment and needs gradually change the organism leading to a different species. |
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Term
| Explain the difference between gradualism & punctuated equilibrium. |
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Definition
| -Punctuated equilibrium says the fossil record came in bits and pieces. Gradualism says evolution comes in slight changes |
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Term
| List & describe pre-reproductive barriers that lead to speciation. |
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Definition
| temporal isolation, habitat isolation, behavioral isolation, mechanical isolation, gametic isolation |
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Term
| List & describe post-reproductive barriers that lead to speciation. |
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Definition
| hybrid infertility, hybrid sterility |
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Term
| Explain directional selection, & give an example. |
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Definition
| form of natural selection in which the entire curve moves; occurs when individuals at one end of a distribution curve have higher fitness than individuals in the middle or at the other end of the curve. ex. fossil records |
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Term
| Explain stabilizing selection & give an example. |
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Definition
| -type of natural selection in which genetic diversity decreases as the population stabilizes on a particular trait value. ex. size of newborn babies |
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Term
| Explain disruptive selection. Give an example. |
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Definition
| form of natural selection in which a single curve splits into two; occurs when individuals at the upper and lower ends of a distribution curve have higher fitness than individuals near the middle. ex. different beak sizes |
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Term
| Explain sexual selection & give an example. |
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Definition
| A form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates. ex. peacocks elaborate tails |
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Term
| Explain genetic drift & give an example. |
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Definition
| changes in the gene pool of a small population due to chance. Tends to reduce genetic variation. ex. bottleneck effect and founders effect |
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Term
| Explain the founders effect & bottleneck effect. Give an example of each. |
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Definition
| A bottle neck is a drastic reduction in population(volcanoes, earthquakes, landslides etc). The allele frequencies of the population before and after Founder effect is when a small population relocates to a location where they have never been to before thus "founding" a new population. |
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Term
| Explain the three principles of natural selection. |
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Definition
| 1Organisms produce offspring with different traits, which can be inherited.2 Organisms produce more offspring than can survive because the world has limited resources.3 Offspring whose traits are best suited to their environment survive and pass on those variations to their offspring. |
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Term
| Describe the five agents of evolutionary change acting on a population. |
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Definition
| 1-Mutation:Usually very low=have little effects on Hardy-Weinberg; best source of genetic variation.2-Gene Flow-Movement of alleles from one population to the next only if the newcomer is genetically different and can survive to reproduce.3-nonrandom mating4-Genetic Drift-Chance events can cause populations to move out of equilibrium:5-Selection |
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Term
| Discuss the anatomical evidence supporting the theory of evolution by natural selection. |
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Definition
| body parts of one species resemble the body parts of another species, accumulating adaptations until structures become more similar on unrelated species |
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Term
| Explain convergent evolution. Give an example. |
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Definition
| This is evolution of two different species towards similar physical characteristics. -Ex: Fins of sharks and dolphins both evolved to propel them through water at faster speeds. |
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Term
| Explain co-evolution & give an example. |
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Definition
| Co-Evolution - the mutual evolutionary influence between two species, affects each others’ evolution, development of mutualism over time (e.g. pollination of Angraecoid orchids by African moths, moths dependent on nectar of flower, flowers dependent on moths to spread their pollen) |
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Term
| Explain how the anatomical record supports evolution. Give an example. |
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Definition
| The Anatomical Record is an official publication of the American Association of Anatomists whose purpose is to rapidly publish new discoveries in the morphological aspects of molecular, cellular,systems, and evolutionary biology. |
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Term
| Discuss the molecular evidence supporting the theory of evolution by natural selection. |
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Definition
| All organisms store their biological history in their DNA. Therefore, evolutionary changes over time should involve a continued accumulation of genetic changes in the DNA. |
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Term
| Discuss the fossil evidence supporting the theory of evolution by natural selection. |
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Definition
| information about past life, including the structure of organisms, what they ate, what ate them, in what environment they lived, and the order in which they lived |
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Term
| Describe the regulation of plant growth by hormone. |
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Definition
Auxins - promote stem elongation, inhibit growth of lateral buds
Cytokinins - stimulates cell division and cell differentation |
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Term
| Describe the three flowering pathways. |
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Definition
| 1-Light Dependent Pathway:Growth and development related to the proportion of light and dark in a day length.2-Temperature Dependent Pathway:Cold temperatures can accelerate or permit flowering. Temp. has an effect on the hormone activity of gibberellins.3-Autonomous Pathway:Plants are independent of their environment in every factor except nutrition. |
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Term
| Explain the relationship between the sporophyte and gametophyte stages of a plant life cycle. |
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Definition
Gametophyte - single set of chromosomes, different by gender
Sporophyte - double set of chromosomes, comes from when the egg is fertilized by the sperm, creating the zygote |
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Term
| Describe the difference between in the epidermal tissue of woody and nonwoody plants. |
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Definition
| Nonwoody: Epidermis is an outer covering protective tissue. Has a waxy cuticle to minimize water loss and in roots has root hairs. Woody: Epidermis is replaced by periderm, which is made of cork cells. Cork cambium is the meristem that produces new cork cells. |
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Term
| Describe the difference between parenchyma, collenchyma, and sclerenchyma ground tissue. |
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Definition
Parenchyma - soft plant tissue made up of thin-walled cells that forms the greater part of leaves, stem pith, roots and fruit pulp.
Collenchyma - layer of supportive plant tissue that consists of elongated living cells that have walls unevenly thickened with cellulose and pectin.
Sclerenchyma - strengthening or supportive walls of plant tissue made up of long cells or fibres and short cells sclereids. |
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Term
| What are the structural differences between xylem and phloem? |
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Definition
| Xylem: Conducts water and mineral solutes upward from roots to leaves. Contains tracheids (small, long cells across which water moves) and vessel elements (serve as pipeline). Phloem: Conducts organic solutes. Contains sieve-tube members (have channels) and companion cells (involved in transport function). |
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Term
| What is the difference between primary and secondary growth? |
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Definition
primary growth occurs at the apical meristems, where the structure is elongated
secondary growth occurs at the vascular cambium and cortex cambium, where the structure is increased in width |
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Term
| Describe the difference between palisades and spongy mesophyll. |
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Definition
| Palisade: Close-packed cylindrical cells, many chloroplasts, no xylem/phloem, no large intercellular spaces. Spongy Mesophyll: Irregular in shape, large intercellular space for gas diffusion, has transport tissues, very few chloroplasts. |
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Term
| Describe how the physical properties of water contribute to transpiration. |
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Definition
| The pulling of water out the stomata at the top puts a tension onto the xylem walls. Water molecules have a cohesive and adhesive quality. The oxygen ends are negatively charged and the hydrogen end are positively charged, so one water molecule will be attracted to other water molecules. |
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Term
| Describe the mechanism by which stomata open and close. |
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Definition
| Stomata open from turgor pressure when guard cells take up water. They close when guard cells lose water and turgor pressure decreases. |
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Term
| What factors affect the rate of transpiration? |
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Definition
| temperature, humidity, wind speed, light intensity, and water supply |
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Term
| Describe the difference between transpiration and translocation. |
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Definition
| Transpiration is movement of water from roots to release of water vapor through leaves. Translocation is movement of organic compounds from the source to the sink. |
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Term
| Disntinguish between photomorphogenesis and phototropism. |
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Definition
Phototropism is plant growth towards a light source.
Photomorphogenesis is the light-induced control of plant growth and differentiation. |
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Term
| Explain how the nonspecific immune system protects against invasion by pathogens. |
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Definition
| There are three lines, the skin, which just acts as a barrier, and a second line, the cellular counterattack. The second line of defense includes macrophages, neutrophils, and natural killer cells. Macrophages and neutrophils eat their attackers, and natural killer cells kill cells and their surrounding cells.Interferons prevent viral replication, and are proteins. These chemicals and proteins create an inflammatory response. |
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Term
| Describe how hydrophilic hormone triggers the response of a target cell. |
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Definition
| Hydrophilic hormones dissolve freely in the blood for to their target cells where they bind with surface membrane receptors.On binding, a hydrophilic hormone triggers a chain of intracellular events by means of a second messenger system that ultimately alters preexisting cellular proteins, usually enzymes, which exert the effect leading to the target cell’s response to the hormone. |
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Term
| Describe how a hydrophobic hormone triggers the response of a target cell. |
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Definition
| A hydrophobic hormone triggers the response of a target cell by directly crossing the cell membrane into the cell. Once inside, it either binds to RNA or DNA, and from there it either turns on or off certain portions of DNA replication. |
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Term
| Describe the regulation of metabolism by thyroxine. |
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Definition
| Thyroxine(T4)- 4 iodine atoms- increases the metabolic rate. -ALL organs respond (in thyroid gland, the largest endocrine gland) |
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Term
| Describe the regulation of blood sugar. |
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Definition
| Blood sugar levels are regulated by negative feedback in order to keep the body in homeostasis. The levels of glucose in the blood are monitored by the cells in the pancreas |
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Term
| Describe the regulation of calcium ion concentration in blood. |
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Definition
| Parathyroid hormone- increases the calcium level in blood & stimulates the absorption of Ca2+ by activating vitamin D, the retention of Ca2+ by the kidneys and demineralization of bone. When it reaches the level-no longer produce PTH (ALL in parathyroid glands) |
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Term
| Explain how B cells protect against invasion by pathogens. |
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Definition
B cells protect vertebrates by producing antigens to combat
pathogens, act as APCs, and become the memory type in order to
effectively combat the same pathogen in the future. |
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Term
| Explain how T cells protect against invasion by pathogens. |
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Definition
| T cells respond to antigens when presented by MHC proteins. |
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