Question

mini-quiz: enzyme specificity
we say that enzymes are specific. what does this mean?
a. the shape of the enzyme’s active site will only catalyze a reaction with a specific substrate or substrates.
b. the enzyme will be able to react with any substrate it encounters because it is able to change its active site to fit any substrate.
c. enzymes are used up and broken down during chemical reactions.
d. none of these.

Explanation:

To determine the correct answer, we analyze each option:

• Option A: Enzyme specificity is based on the active site's shape, which is complementary to specific substrates, allowing catalysis of reactions only with those substrates. This matches the concept of enzyme specificity.
• Option B: Enzymes do not change their active site to fit any substrate; the active site has a specific shape (lock - and - key or induced - fit model, but still specific). So this is incorrect.
• Option C: Enzymes are not used up in chemical reactions; they can be reused. So this is incorrect.
• Option D: Since Option A is correct, D is incorrect.

Answer:

A. The shape of the enzyme's active site will only catalyze a reaction with a specific substrate or substrates.