Pearson Edexcel AS Level · Biology B (8BI0)

Enzymes: Practice Questions

3 multiple-choice questions marked as you go, and 3 written questions with worked solutions. All on Enzymes.

6 questions14 marksFree, no account
Question 1
1 mark

An experiment was conducted to investigate the effect of substrate concentration on the rate of an enzyme-controlled reaction. At very high substrate concentrations, the rate of reaction levels off and becomes constant. What is the most likely reason for this observation?

Question 2
1 mark

A non-competitive inhibitor is added to a reaction mixture containing an enzyme and its substrate. How will the addition of this inhibitor affect the maximum rate of reaction (\(V_{max}\)) and the affinity of the enzyme for its substrate?

Question 3
1 mark

In the study of enzyme kinetics, the induced fit hypothesis is often preferred over the lock and key model. Which statement best describes the induced fit hypothesis?

Question 4
3 marks

Explain why measuring the initial rate of an enzyme-controlled reaction is more accurate than measuring the average rate over the entire duration of the reaction.

Write your answer out first, then check it against the worked solution.

Question 5
5 marks

An enzyme-controlled reaction has an activation energy of \(E_a\). Explain, in terms of molecular collisions and energy levels, how the addition of a specific globular protein catalyst alters this value.

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Question 6
3 marks

Using the induced fit hypothesis, describe how the shape of an enzyme's active site changes when a substrate molecule binds to it.

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