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Description
Flashcards by Talya Hambling, updated more than 1 year ago
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Created by Talya Hambling
over 8 years ago
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| Question | Answer |
| what's is an enzyme | a biological catalyst that speeds up a reaction without being used up |
| what are enzymes made from | proteins (and therefore chains of amino acids) |
| describe activation energy | the energy needed to start a reaction, often heat |
| when an substrate locks into an enzyme, what does it become | an enzyme substrate complex |
| name the two models for enzyme action | the lock and key model ,and the induced fit model |
| describe the lock and key model | the substrate is complimentary to the active site, and locks into the correct one |
| describe the induced fit model | the substrate and active site aren't completely complimentary, but rather the enzyme changes its shape to fit around the correct substrate, like a hand in a glove |
| what is the shape of an enzyme dictated by | its tertiary structure. if it is altered (by heat of pH etc.) the active site will no longer work |
| what 4 factors affect enzyme activity | temperature, pH, substrate concentration and enzyme concentration |
| how does temperature affect enzyme activity | more kinetic energy means substrates/enzymes will collide faster, increasing the rate of reaction. However above 40 the active site changes shape and the enzyme denatures |
| how does pH affect enzyme activity | human enzymes work best at pH 7 (neutral). above or below that makes the enzymes denature, and causes their bonds to break. |
| how does substrate concentration affect enzyme activity | more substrates means a faster rate of reaction, until all of the active sites are full. With time, substrate concentration decreases though. |
| how does enzyme concentration affect enzyme activity | more enzymes means more available collisions to create an enzyme substrate complex, until all substrates have an active site and no more enzymes are needed. |
| what is a competitive inhibitor | a molecule with a similar shape to the substrate, which also fits into the active site, blocking the formation of an enzyme substrate complex. |
| what is a non competitive inhibitor | a molecule that binds to another part of the enzyme, causing the whole enzyme to change shape and therefore the substrate will no longer fit the active site. |
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