Enzymes as Biocatalysts

Enzymes as Biocatalysts MDCAT MCQs with answers

5 past paper MCQs on Enzymes as Biocatalysts, from the Macromolecules unit of MDCAT Chemistry. The year each question appeared is shown where known; tap “Show answer” for the correct option and a short solution.

Read the notes first Practise the unit as a quiz

1.Which of the following enzymes is raised in rickets? (MDCAT 2020)

  1. lactic dehydrogenase
  2. alkaline phosphatase
  3. amylase
  4. lipase
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Correct answer: (b) alkaline phosphatase

Bone turnover is high in rickets, and the osteoblasts release alkaline phosphatase into the blood.

2.When food reaches the stomach, the action of which enzyme comes to an end because of the acidic pH? (MDCAT 2022)

  1. lipase
  2. amylase
  3. maltase
  4. hydrolases
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Correct answer: (b) amylase

Salivary amylase works near neutral pH and is denatured by the acid of the stomach.

3.Inhibitors stop an enzyme from working by: (MDCAT 2023)

  1. changing the shape of the enzyme
  2. merging with the substrate instead
  3. blocking the active site of the enzyme
  4. combining with the product of the reaction
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Correct answer: (c) blocking the active site of the enzyme

A competitive inhibitor occupies the active site, so the substrate cannot bind there.

4.Urease is present in: (PMC Practice 2021)

  1. Yeast
  2. Grapes
  3. Soya sauce
  4. Soya bean
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Correct answer: (d) Soya bean

Urease, the first enzyme to be crystallized, is got from soya bean.

5.L – Asparaginase enzyme has been used for the treatment of: (PMC MDCAT 2020)

  1. Jaundice
  2. Blood cancer
  3. Rickets
  4. Heart disease
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Correct answer: (b) Blood cancer

L-asparaginase starves leukaemic cells of asparagine and is used against blood cancer.

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