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38 Cards in this Set
- Front
- Back
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fluid mosaic model |
*structure of a membrane structure *diverse proteins molecules suspended in a fluid phospholipid layer |
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selectve permeability |
*the membrane only allows some substances to cross more easily than others *REVIEW PICS ON 5.1 |
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membrane formation |
*critical step in evolution (phosphlipid layer) *allows the cells to regulate chemical exchanges with the environment |
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diffusion |
the tendency of particles of a substance to spread out into available space *net movement from higher concentration to lower concentration (concentration gradient) |
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passive transport |
*when cells don't have to do work bc the molecules flow through their concentration gradient *O2 entering the cell, CO2 exiting |
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osmosis |
diffusion of water across a selectively permeable membrane |
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tonicity |
*the ability of a surrounding solution to cause a cell to gain or lose water |
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isotonic |
*same amount of solute concentration, cell's volume remains constant *gains water at the same rate that it loses it |
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hypotonic |
*when a cell is placed in an environment with a lower solute concentration than the cell *cell gains water,swells,and can burst *plant cells are always in this state with the cell wall pushing against the excess water and preventing it from taking in too much H2O |
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hypertonic |
*environment has a higher solute concentration than the cell *water exits cell and can shrivel and die from water loss *plant cell shrivels too |
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osmoregulation |
the control of water balance *to help animal cels survive |
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facilitated diffusion |
*passive transport (no energy required) *transport proteins help hydrophilic ions cross -can also change shape to bind with its passenger and releases the passenger on the other side |
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aquaporin
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*protein channels that allow fro the rapid diffusion in and out of a cell for cells who need a rapid supply of water *very common in red blood cells, discovered by studyingRh proteins *only allow what to pass through |
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active transport |
*cells expend energy to move a solute against its concentration gradient *typically ATP * allows a cell to maintain internal concentration of small molecs *proteins bind to solute, change shape to release on the other side, returns to original shape *ex. sodium-potassium pump that keeps levels of Na outside and K inside the cell normal |
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exocytosis |
*exports bulky materials like proteins or polysacchs *Transport vesicle buds from the golgi and moves to plasma membrane, vesicle's contents spill out and vesicle becomes part of plasma membrane |
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endocytosis |
how a cell takes in large molecs |
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phagocytosis |
*type of endocytosis *cell engulfs particle by wrapping extensions around it and packaging it within a vacuole, which fuses with a lysosome so that it can digest the vacuole |
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receptor-mediated endocytosis |
*enables a cell to acquire specific solutes *receptor proteins are embedded in the membrane indent where the proteins collect molecules that fit the protein, the indent forms a vesicle which then releases molecules into the cytoplasm |
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cellular respiration |
chemical energy stored in organic molecules is used to produce ATP *waste is CO2 and H2O 34% efficient *cells try to maintain low entropy |
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exergonic rxn |
releases energy *PE of reactants is higher than that of the products, releasing energy *release energy in the form of cellular respiration, heat or ATP |
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endergonic rxn |
*require energy *reactants have less PE than the products *photsynthesis |
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metablosim |
total of an organism's chemical rxns |
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metabloic pathway |
series of chemical rxns that either builds a complex molec or breaks down a complex molec |
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energy coupling |
*use of energy released from exergonic runs to drive endergonic rxns |
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ATP |
powers nearly all forms of cellular work *phosphate group leaves ATP becomes ADP *hydrolysis of ATP is exergonic |
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phosphorylation |
*transferring a phosphate group from ATP to another molec to couple the exergonic run of ADP to another *provides energy to drive endergonic rxns |
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activation energy |
the energy required fro the reactants to move uphill to a higher energy and unstable state so the downhill pat of the rxn can begin *can speed up by adding heat or enzymes |
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enzymes |
*speed up run by lowering the activation energy needed to start the rxn *temperature affects the rate of contact bw reactants and active sites, can denature the enzyme *pH need stop be ideally between 6-8 |
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substrate |
*the specific reactant that an enzyme act on *fits into the active site of an enzyme *REVIEW 5.14 STEPS AND PICTURE |
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induced fit |
*active site changes shape slightly to embrace the substrate snuggly |
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cofactors |
*nonprotein helpers * bind to the active sit and fun in catalysis |
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coenzyme |
*if the cofactor is an organic molecule |
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inhibition |
*when a chemical interferws with an enzyme's activity *helps regulate cellular metabolism |
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competitive inhibitor |
*reduces an enzymes productivity by blocking substrate molecs from entering the active site *can be overcome by increasing the concentration of the substrate |
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noncompetitive inhibitor |
*binds to a site elsewhere on the enzyme which changes the enzyme shape so that the active site won't fit the substrate |
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feedback ihibition |
*when the product acts as an inhibitor early in the pathway *reversible |
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ibuprofen |
inhibitor that stops the enzyme involved in the production pain molecules |
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poisons |
*irreversible inhibition, ex nerve endings- causes paralysis/death |
