Question 1

Which of the following best describes noncompetitive inhibition of an enzyme?

Accepted Answer

The inhibitor binds to a site other than the active site, causing a conformational change that reduces enzyme activity.

Question 2

A patient is given a drug that increases the $$K_m of an $$enzyme but does not affect $$V_{max}. $$What type of inhibition is this drug exhibiting?

Accepted Answer

Competitive inhibition

Question 3

Which of the following statements about feedback inhibition in metabolic pathways is correct?

Accepted Answer

The end product of the pathway inhibits the first enzyme, preventing overproduction.

Question 4

Which of the following vitamins is fat-soluble and stored in the liver?

Accepted Answer

Vitamin D (calciferol)

Question 5

Which of the following best explains why water-soluble vitamins must be consumed regularly in the diet?

Accepted Answer

They are not stored in the body and excess amounts are excreted in urine.

Question 6

Which vitamin is ingested in its provitamin form as $$\beta-$$carotene and is essential for vision?

Accepted Answer

Vitamin A

Question 7

A patient with a deficiency in thiamine (vitamin B1) is likely to have problems with which metabolic process?

Accepted Answer

Decarboxylation of substrates in carbohydrate metabolism

Question 8

Which of the following statements about coenzymes is correct?

Accepted Answer

Coenzymes are organic molecules, often derived from water-soluble vitamins, that assist enzymes in catalysis.

Question 9

Which of the following is a function of vitamin K in the human body?

Accepted Answer

Required for the formation of prothrombin, essential for blood clotting

Question 10

A simple blood test for a suspected heart attack often measures the activity of which enzyme?

Accepted Answer

Creatine kinase (CK or CPK)

Question 11

Which of the following best describes the mechanism of action for irreversible enzyme inhibitors?

Accepted Answer

They form a covalent bond with the enzyme, permanently inactivating it.

Question 12

Which of the following statements about zymogens is correct?

Accepted Answer

Zymogens are inactive enzyme precursors that require removal of a peptide segment to become active.

Question 13

Which of the following vitamins is required for the synthesis of collagen and acts as an antioxidant?

Accepted Answer

Vitamin C (ascorbic acid)

Question 14

Which of the following best describes the effect of a noncompetitive inhibitor on enzyme kinetics?

Accepted Answer

$$V_{max}$$ decreases, $$K_m$$ remains unchanged.

Question 15

Which vitamin deficiency is most likely to result in neural tube defects in a developing fetus?

Accepted Answer

Vitamin B9 (folic acid)

Question 16

The lateral flow assay used in COVID-19 rapid tests relies on which class of proteins to detect viral antigens?

Accepted Answer

Antibodies

Question 17

Which of the following statements about allosteric regulation is correct?

Accepted Answer

Allosteric regulation can either increase or decrease enzyme activity depending on the regulator.

Question 18

Which coenzyme is derived from riboflavin (vitamin B2) and is involved in redox reactions?

Accepted Answer

Flavin adenine dinucleotide (FAD)

Question 19

Which of the following best describes the role of covalent modification in enzyme regulation?

Accepted Answer

It involves the addition or removal of a chemical group, such as a phosphate, to alter enzyme activity.

Question 20

Which of the following statements about $$K_m is $$correct?

Accepted Answer

$$K_m is $$the substrate concentration at which the reaction rate is half of $$V_{max}.$$

Regulation, Vitamins, and Their Significance to Enzyme Function; Serological Testing

Study Guide - Practice Questions