Term
| What are the 3 main function of the plasma membrane? |
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Definition
| 1. Forms a cells outer boundary 2.Separates the cells internal environment (inside) from its external environment (outside) 3. Regulates the flow of materials into and out of a cell maintaining the appropriate environment for normal cellular activities |
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Term
| What is the cytoplasm of the cell? |
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Definition
| All the cellular contents between the plasma membrane and the nucleus |
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Term
| What are the 2 subcomponents of the cytoplasm? |
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Definition
| 2 sub components: cytosol & organelles: 1. Cytosol - the fluid portion of cytoplasm mostly water plus dissolved solutes & suspended particles |
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Term
| What is the largest organelle in the cell? |
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Definition
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Term
| What are the two main functions of the nucleus? |
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Definition
| 1. Contains the genes that control cellular structure 2.Controls most cellular activities |
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Term
| What are the components of the cytoskeleton and what is its function? |
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Definition
| Made of three things 1.microfilaments 2. intermediate filaments and 3. microtubules. It functions to maintain shape and general organization of cellular contents responsible for cell movements. |
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Term
| What is the function of the centriole? |
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Definition
| This is the organizing center for microtubules and mitotic spindle. |
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Term
| What is the function cilia and flagella and what are they made of? |
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Definition
| cilia and flagella are both used to propel the cell through their environment. Both are made of microtubules. |
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Term
| What is the function of ribosomes? What type of RNA are they composed of? |
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Definition
| Ribosomes are responsible for protein synthesis and are made of rRNA |
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Term
| What are the two types of endoplasmic reticulum and what do each do? |
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Definition
| 1. rough ER and 2. smooth ER. Rough ER synthesizes proteins that have sugars attached to them (called glycoproteins) and are always exported from the cell. Rough ER has ribosomes attached to the outside and is found around the nucleus. Smooth ER is the site of fatty acid and steroid synthesis. Smooth ER also releases glucose intot the bloodstream, inactivates and detoxifies drugs and potentially harmful substances and stores and releases calcium ions for muscle contraction. |
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Term
| What is the Golgi complex and what does it do? |
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Definition
| Accepts proteins from the rough ER; forms glycoproteins and lipoproteins; stores, packages and exports proteins. |
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Term
| What are lysosomes and what do they do? |
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Definition
| The fuse with and digest contents of vesicles; digest worn out organelles (called autophagy) and the entire cell (called autolysis) and extracellular material. They are sometimes called suicide packets because they may release hydrolytic enzymes that lead to autolysis of the cell. |
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Term
| What is the function of peroxisomes? |
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Definition
| They detoxify harmful substances such as hydrogen peroxide and associated free radicals |
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Term
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Definition
| These degrade unneeded, damaged or faulty proteins by cutting them into small peptides |
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Term
| What is a mitochondria and what is its function? |
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Definition
| Mitochondria is the site of reactions that produce ATP; the cells currency and most important form of energy. It does this under aerobic cellular respiration (a type of catabolism that requires oxygen). Besides the nucleus, they are the only other organelle capable of self replication. |
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Term
| What are the two main contents of the membrane? |
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Definition
| Consists mostly of lipids (fats) and proteins arranged in a lipid bilayer (a double layer) |
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Term
| What are the 3 types of fats found in the membrane? Which are the most and least common? |
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Definition
| Made of 3 types of lipid molecules: 1. Phospholipids - (lipids & phosphorus) forms the lipid bilayer and is the most numerous component |
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Term
| What are the 2 general types of proteins found in the membrane? |
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Definition
| Made of 2 types of proteins: 1. Integral proteins - extend through the lipid bilayer among the fatty acid tails (may allow water soluble molecules through) 2.Peripheral proteins - loosely attached to the surfaces of the membrane (often glycoproteins) |
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Term
| What does it mean that the membrane is selectively permeable? |
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Definition
| Selective permeability, allows some components to pass through but not others |
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Term
| What types of molecules can passively diffuse through the membrane? |
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Definition
| The lipid bilayer part is permeable to water and to nonpolar (lipid soluble) molecules, such as fatty acids, fat-soluble vitamins, steroids, oxygen, and carbon dioxide |
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Term
| What types of molecules can not cross the membrane without the help of a protein? |
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Definition
| It is not permeable to ions and large, uncharged polar molecules such as glucose and amino acids |
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Term
| How do molecules that do not cross the membrane via passive diffusion get into the cell? |
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Definition
| Water-soluble materials may cross the membrane with the help of integral proteins |
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Term
| What types of things can integral membrane proteins do? |
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Definition
| Integral proteins form receptors and ion channels (ions such as potassium can move into and out of cells). They can also function as enzymes or as carriers (transporters) that move things across the cell membrane. |
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Term
| What are the 2 general ways that molecules can cross the membrane? |
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Definition
| 1. passively and 2. actively (it requires ATP) |
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Term
| What are the 4 types of passive transport? |
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Definition
| 1. simple diffusion 2. osmosis 3. facilitated diffusion and 4. filtration |
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Term
| What are the 2 types of transport that require ATP? |
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Definition
| 1. active transport and bulk transport (like pinocytosis, phagocytosis and receptor mediated endocytosis) |
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Term
| What are the 3 main characteristics of passive diffusion (this includes simple diffusion, facilitated diffusion, osmosis and filtration)? |
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Definition
| 1.A substance moves due to its kinetic energy 2.A particular substance moves from a high to a low concentration, down their concentration gradient 3.Eventually equilibrium (uniform mixture) is reached |
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Term
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Definition
| Simple diffusion, substances diffuse across a membrane through the lipid bilayer |
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Term
| Define facilitated diffusion? |
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Definition
| Facilitated diffusion, an integral membrane protein binds a specific substance to move it across the membrane |
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Term
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Definition
| A passive process with net movement of water through a selectively permeable membrane |
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Term
| In what direction does water move into and out of the cell? |
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Definition
| Water moves by osmosis from an area of higher concentration to an area of lower water concentration Or from an area of lower solute concentration to an area of higher solute concentration |
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Term
| What is osmotic pressure? What determines it's magnitude? |
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Definition
| A solution containing solute particles that cannot pass through a membrane exerts a pressure on it called osmotic pressure. Osmotic pressure of a solution depends on the concentration of its solute particles (the higher the solute concentration, the higher the solutions osmotic pressure) |
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Term
| What is an isotonic solution? give an example? |
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Definition
| The osmotic pressure of cytosol and interstitial fluid is the same, so the cell volume remains constant. This is an isotonic (same tone) solution |
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Term
| What is a hypotonic solution? |
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Definition
| A hypotonic solution - a lower concentration of solutes (or higher concentration of water) than does the cytosol inside cells |
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Term
| What is a hypertonic solution? |
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Definition
| A hypertonic solution - a higher concentration of solutes (or lower concentration of water) than does the cytosol inside cells |
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Term
| What causes red blood cells to crenate? |
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Definition
| Being placed in a hypertonic solution; the water inside a red blood cell will leave the cell and cause the cell to shrivle or crenate. |
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Term
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Definition
| Filtration is when water and solutes are forced through the membrane by hydrostatic pressure (the pressure of the fluid moving through a finite space) |
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Term
| What drives filtration into or out of a space? |
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Definition
| Requires a pressure gradient of high to low |
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Term
| Why would a particle not be filtered out of the blood (in other words, what is the selectivity factor for filtration)? |
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Definition
| Size of the particles is a limiting factor |
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Term
| Where does filtration take place in the body? |
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Definition
| the nephron of the kidney to filter the blood |
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Term
| When is active transport used by a cell instead of passive transport? |
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Definition
| Used to move large lipid insoluble molecules against their gradient. Also known as solute pumping |
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Term
| Besides ATP, what else is required for active transport? |
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Definition
| Requires carrier proteins that are specific to the substance needed to cross the membrane |
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Term
| What is the most important active transporter used by cells? How does it work? |
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Definition
| Expels sodium ions (Na) from cells and brings in potassium ions (K). The pump protein also acts as an enzyme to split ATP. Maintains a low sodium ion concentration in the cytosol. Works continuously since the ions slowly diffuse back with the concentration gradient |
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Term
| Describe the 4 main steps involved in transport that the sodium/potassium pump goes through? |
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Definition
| 1) 3 sodium ions (Na) in the cytosol bind the pump protein 2) Na binding triggers the splitting of ATP into ADP +P, which also attaches to the pump protein. Changing the shape of the pump protein. This expels the 3 Na into the extracellular fluid (ECF). The changed shape of the pump protein then favors binding 2 potassium ions (K) in the ECF to the pump protein 3) The binding of K causes the pump protein to release the P group, which causes the pump protein to return to its original shape 4) Changing shape releases 2 K into the cytosol. Now, the pump is ready again to bind Na, and the cycle repeats |
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Term
| Define exocytosis and endocytosis? |
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Definition
| 1) Exocytosis secretion or excretion of materials out of the cell 2) Endocytosis the cell engulfs or forms vesicles around materials |
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Term
| What are the 3 types of endocytosis?Describe each. |
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Definition
| 3 types of Endocytosis: 1. Pinocytosis cell drinking 2. Phagocytosis cell eating (done by macrophages and neutrophils... more on these later) 3. Receptor Mediated binding to the membrane & pits are formed |
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Term
| What are the two main types of cells that can carry out phagocytosis? |
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Definition
| 1. Macrohpages responsible for most of the phagocytosis that goes on in the cell 2. Neutrophils these are the first cells that are localized to the site of infection and are required for remove pathogens |
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Term
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Definition
| Cytoplasm - all of the cellular contents from the plasma membrane & the nucleus, including both cytosol & organelles |
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Term
| What is the cytosol? What is it composed of? What happens there? |
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Definition
| Cytosol - 75% to 90% water plus dissolved solutes & suspended particles. The site of many of the chemical reactions to maintain cell structures and growth. |
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Term
| What are the 3 cytoskeleton components? |
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Definition
| 1. microfilaments 2. intermediate filaments and 3. microtubules |
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Term
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Definition
| Microfilaments anchoring support & movement (i.e. In the contraction of skeletal muscle) |
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Term
| What are intermediate filaments? |
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Definition
| Intermediate filaments flexible anchors holding cell components in place |
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Term
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Definition
| Microtubules cell structure & movement of cell vesicles, cilia and flagella (e.g., centrosome) (also, cilia contain a core of microtubules) |
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Term
| What is the most numerous organelle in the cell? |
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Definition
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Term
| What are the two components of the ribosome? |
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Definition
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Term
| What are the two types of ribosomes? Describe each? |
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Definition
| 1) Membrane bound Ribosomes - Bound to the Endoplasmic rough Reticulum Site of protein synthesis (proteins destined to be on the outer cell surface or excreted) 2) Free ribosomes make soluble proteins for use in the cytoplasm |
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Term
| What is the endoplasmic reticulum? What are the two types? |
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Definition
| Network of folded membranes in the form of flattened tubules 2 forms: Rough and Smooth ER |
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Term
| What is the function of the rough ER? |
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Definition
| Rough ER: synthesizes glycoproteins & phospholipids that are transferred into cellular organelles, inserted into the outer leaflet of the plasma membrane or secreted during exocytosis |
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Term
| What is the function of the smooth ER? |
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Definition
| Smooth ER: synthesizes fatty acids and steroids (e.g., estrogens, testosterone) Inactivates or detoxifies drugs and other potentially harmful substances. Removes the phosphate group from glucose-6-phosphate & stores |
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Term
| What is autolysis and what organelle does this? |
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Definition
| During programmed cell death, lysosomes will rupture their membrane and all the hydrolytic enzymes will digest the contents of the cell (called autolysis) |
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Term
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Definition
| Autophagy is the normal recycling of worn out organelles where their components are recycled |
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Term
| How many membranes does a mitochondria have? Describe each. |
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Definition
| Sausage shaped structure with folds smooth outer folds and rougher inner folds called cristae which increase the surface area for chemical reactions. Mitochondria have a double membrane |
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Term
| Where are mitochondria often found? |
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Definition
| Found in areas with high energy requirements E.g., Muscle |
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Term
| Can mitochondria replicate themselves? Do they contain genetic information? |
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Definition
| Self replicating & contain both DNA & RNA |
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Term
| What are the three main things in the nucleus? |
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Definition
| Consists of nuclear envelope (membrane) with pores and chromatin (chromosomes) the genetic material. Also contain nucleolus that produces ribosomes (rRNA). |
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Term
| How many chromosomes do humans have? |
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Definition
| Human somatic (body) cells have 46 chromosomes, 23 inherited from each parent (known as a diploid (2n) number of chromosomes. |
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Term
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Definition
| The total genetic information carried in a cell or organism is called its genome. |
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Term
| How is a protein made from DNA? |
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Definition
| To synthesize a protein, the information contained in a specific region of DNA is first transcribed (copied from DNA into RNA). The RNA then attaches to a ribosome, where the information contained in the RNA is translated into a corresponding specific sequence of amino acids to form a new protein molecule. |
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Term
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Definition
| The 3 RNA nucleotides that code for an amino acid are called a codon (or base triplet) |
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Term
| What is protein a polymer of? |
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Definition
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Term
| What enzyme catalyzes RNA synthesis? |
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Definition
| Transcription of DNA is catalyzed by the enzyme RNA polymerase |
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Term
| What is a promoter? Where is it found? |
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Definition
| The segment of DNA where RNA polymerase attaches to it is a special sequence of nucleotides called a promoter. Located near the beginning of a gene to start the process |
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Term
| What are the 3 kinds of RNA? describe each. |
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Definition
| Three kinds of RNA are made from DNA: 1 Messenger RNA (mRNA) directs synthesis of a protein in the cytoplasm 2 Ribosomal RNA (rRNA) joins with ribosomal proteins to make ribosomes in the nucleolus 3 Transfer RNA (tRNA) binds to an amino acid holding it in the cytoplasm |
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Term
| What is complimentary base pairing? |
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Definition
| Cytosine (C) pairs with the base guanine (G) and uracil (U) pairs with the base adenine (A) in DNA |
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Term
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Definition
| Transcription of DNA ends at another special nucleotide sequence on DNA called a terminator, which specifies the end of the gene |
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Term
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Definition
| Translation is the process in which mRNA associates with ribosomes and synthesizing a protein by converting the sequence of nucleotides in mRNA into a specific sequence of amino acids. |
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Term
| What are the 5 steps of translation? |
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Definition
| 1) The large ribosomal subunit attaches to the small subunit, creating a functional ribosome. The initiator tRNA fits into position on the ribosome. One end of a tRNA carries a specific amino acid, & the opposite end consists of a triplet of nucleotides called an anticodon 2) By pairing between complementary nitrogenous bases, the tRNA anticodon attaches to the mRNA codon E.g., if the mRNA codon is AUG, then a tRNA with the anticodon UAC would attach to it 3) A peptide bond is formed between the amino acids carried by the initiator tRNA and the tRNA next to it 4) After the peptide bond forms, the empty tRNA detaches from the ribosome, and the ribosome shifts the mRNA strand by one codon. As the tRNA bearing the newly forming protein shifts, another tRNA with its amino acid binds to a newly exposed codon. 5) Protein synthesis ends when the ribosome reaches a stop codon, at which time the completed protein detaches from the final tRNA. When the tRNA vacates the ribosome, theribosome splits into its large and small subunits |
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Term
| What is cell division? What is it also called? |
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Definition
| Cell division is also called mitosis (2 identical daughter cells are formed from the original mother cell; 46 chromosomes in each cell known as a diploid (2n) number of chromosomes) |
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Term
| What is reproductive cell division? |
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Definition
| Reproductive cell division is meiosis resulting in gametes (cells divide to produce 4 cells with half of the genetic material as the original cell i.e., eggs or sperm also known as gametes or sex cells). This is also where genetic recombination and crossing over occurs. |
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Term
| What are the two main phases of the cell cycle? |
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Definition
| The Cell cycle is composed of 2 main phases: 1) Interphase (Growth) phase 2) Mitotic (Dividing) Phase |
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Term
| What 3 main things happen during interphase? |
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Definition
| 1.The cell replicates its DNA 2.It manufactures organelles and cytosolic components, such as centrosomes 3. Interphase is a state of high metabolic activity, and during this time the cell does most of its growing |
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Term
| What are the 4 phases of mitosis? |
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Definition
| 1. prophase 2. metaphase 3.anaphase and 4.telophase |
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Term
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Definition
| Prophase chromatid pairs form and collect around the metaphase plate of the cell |
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Term
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Definition
| Metaphase chromatid pairs line up at the plate |
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Term
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Definition
| Anaphase chromatids that have separated move to opposite ends of the poles |
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Term
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Definition
| Telophase final stage where the nuclear envelope reforms |
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Term
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Definition
| Cytokinesis - division of the cytoplasm into 2 cells |
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Term
| What are the 4 things that cause aging to occur? |
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Definition
| 1. Gradual deterioration in function and reduced capacity to respond to environment 2. The turning on of an aging gene at a pre-programmed time 3. Alteration of cells by free radicals and or cross links formed by glucose 4. Gradual deterioration of the ends of chromosomes called telomeres |
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Term
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Definition
| Necrosis Premature death of tissue caused by some external factor. |
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Term
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Definition
| Apoptosis programmed cell death that happens as the nature cycle of cells. |
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Term
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Definition
| Cancer cells that move from one site to another are known as metastasis |
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Term
| What are malignant tumors? |
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Definition
| Malignant tumors are ones that tend to cause the worst form of the disease and often result in death; this is especially true of malignant cancer |
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Term
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Definition
| A benign tumor is a tumor that lacks all three of the malignant properties of a cancer. Thus, by definition, a benign tumor does not grow in an unlimited, aggressive manner, does not invade surrounding tissues, and does not metastasize. |
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Term
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Definition
| Leukemia this is a cancer of blood forming organs that is characterized by abnormally developed white blood cells |
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Term
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Definition
| Carcinoma is the general term for a malignant tumor of epithelial tissue |
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Term
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Definition
| Melanoma Tumor of melanocytes (the pigment producing cells of the skin) |
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Term
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Definition
| Sarcoma is the cancer of connective tissue (bone, cartilage and fat) |
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