Enzymes

Q1: What is an enzyme?
A: A biological catalyst that speeds up chemical reactions by lowering activation energy.

Q2: What is a substrate?
A: The specific molecule that an enzyme acts upon.

Q3: What is the active site?
A: The region on the enzyme where the substrate binds.

Q4: What is the enzyme-substrate complex?
A: A temporary complex formed when the enzyme binds its substrate.

Q5: What does it mean for an enzyme to be specific?
A: It only acts on one or a few specific substrates due to the shape of its active site.

Q6: What happens to an enzyme after a reaction?
A: It remains unchanged and can be reused.

Q7: What is activation energy?
A: The minimum energy required for a chemical reaction to start.

Q8: How do enzymes affect activation energy?
A: They lower it, allowing reactions to occur faster and with less energy.

Q9: What is a coenzyme?
A: A small organic molecule that assists enzyme function (e.g., vitamins).

Q10: What is a cofactor?
A: A non-protein helper (often metal ions) required for enzyme activity.

Q11: What is a competitive inhibitor?
A: A molecule that competes with the substrate for the active site.

Q12: What is a noncompetitive inhibitor?
A: A molecule that binds to another part of the enzyme, changing its shape and reducing function.

Q13: What is feedback inhibition?
A: A process where the end product of a pathway inhibits an earlier enzyme in that pathway.

Q14: How does temperature affect enzyme activity?
A: Activity increases with temperature to a point, then drops if the enzyme denatures.

Q15: How does pH affect enzyme activity?
A: Each enzyme has an optimal pH; too high or too low can denature it.

Q16: What is denaturation?
A: The loss of an enzyme’s shape, resulting in loss of function.

Q17: Why are enzymes crucial for metabolism?
A: They regulate the rate of all chemical reactions in cells.

Q18: What is an allosteric site?
A: A site other than the active site where molecules can bind and regulate the enzyme.

Q19: What is enzyme saturation?
A: A state where all active sites are occupied, and adding more substrate doesn’t increase the reaction rate.

Q20: Why are enzyme-catalyzed reactions reversible?
A: Many enzymes can catalyze both forward and reverse reactions depending on conditions.