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MDCAT
Biology
2009

Biology · Enzymes

Work through this past-paper style MCQ, then read the full explanation. Practice more biology questions on mMCQ with adaptive practice and topic analytics.

Question

Which one of the following statements is NOT true for enzymes?

Options
  • A

    They lower the activation energy

  • B

    They decrease the rate of reaction

  • C

    They are specific in their action 

  • D

    They are present at the end of the reaction

  • E

    They are pH sensitive

Explanation

Enzymes, in fact, increase the rate of chemical reactions by lowering the activation energy required for the reaction to occur. They do not decrease the rate of a reaction.

Enzymes lower the activation energy, making it easier for a chemical reaction to occur.

Enzymes, in fact, increase the rate of chemical reactions by lowering the activation energy required for the reaction to occur. They do not decrease the rate of a reaction.

Enzymes are highly specific in their action. Each enzyme typically catalyzes a specific reaction or set of reactions.

Enzymes are not present at the end of the reaction. They remain unchanged after the reaction and can be used again in subsequent reactions.

Enzymes can be pH-sensitive, meaning they may have an optimal pH at which they function most efficiently. Changes in pH can affect enzyme activity.

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Tagged under Biology · Enzymes · 2009