Free Biochemistry Enzymes and Metabolism Questions and Answers

Question 1

Which of the following statements about enzymes is TRUE?

Accepted Answer

Enzymes lower the activation energy of a reaction.

Answer

Enzymes are consumed during the reaction.

Answer

Enzyme activity is independent of temperature and pH.

Answer

All enzymes require cofactors to function.

Question 2

In glycolysis, which enzyme catalyzes the conversion of glucose to glucose-6-phosphate?

Accepted Answer

Hexokinase

Answer

Phosphofructokinase

Answer

Pyruvate kinase

Answer

Aldolase

Question 3

Which of the following is a key regulatory enzyme in the citric acid cycle?

Accepted Answer

Isocitrate dehydrogenase

Answer

Citrate synthase

Answer

Succinate dehydrogenase

Answer

Malate dehydrogenase

Question 4

During oxidative phosphorylation, the final electron acceptor in the electron transport chain is:

Accepted Answer

Oxygen (O₂)

Answer

NAD⁺

Answer

FAD

Answer

Water (H₂O)

Question 5

Which of the following statements about competitive inhibition is TRUE?

Accepted Answer

Competitive inhibitors bind to the active site of the enzyme.

Answer

Competitive inhibitors reduce the Vmax of an enzyme.

Answer

Competitive inhibition cannot be overcome by increasing substrate concentration.

Answer

Competitive inhibitors form covalent bonds with the enzyme.