write up

Question 1

controlled by presence or absence of enzymes and…

Answer 1

• regulation of the rate of reaction of key enzymes
• enzymes are biological catalysts which speed up chemical reactions by lowering the activation energy needed for the reaction to occur and they remain unchanged

Question 2

induced fit

Answer 2

when the active site changes shape to better fit the substrate
1. active site begins in open position
2. substrate molecules have high affinity for active site
3. due to strong chemical reaction it binds to form enzyme/substrate complex

Question 3

activation energy (after induced fit)

Answer 3

activation energy lowered allowing product to form
- products have diff shape than substrate leading to them having low affinity for active site therefore leaving the active site
- active site returns to open shape allowing other substrates to bind continuing the reaction

Question 4

inhibitor

Answer 4

a substance which slows down or inhibits the rate of an enzyme catalysed reaction
- controlled by feedback, competitive and none competitive inhibitors

Question 5

types of inhibitors

Answer 5

competitive:
- similar shape to substrate
- they bind with enzymes to decrease activity as substrate has a less chance of binding at active site

non competitive:
- bind to another part of enzyme away from active site which changes the shape of active site preventing substrate to bind

feedback inhibition:
- control mp
- occurs when end product in mp reaches a critical concentration
- end product of reaction inhibits an earlier enzyme blocking pathway to prevent synthesis of product

Question 6

aim

Answer 6

to investigate the effect of substrate concentration on enzyme activity

Question 7

method

Answer 7

into four measuring cylinders equal concentrations of hydrogen peroxide, detergent a pH buffer solution and catalase was added. the volume of foam produced after 2 minutes was measured using the measuring cylinders. this experiment was repeated for each buffer solution.