Question 1

Which of the following best describes competitive inhibition in enzyme activity?

Accepted Answer

The inhibitor resembles the substrate and competes for the active site.

Question 2

Which equation correctly describes the Michaelis constant ($$K_m) $$for an enzyme-catalyzed reaction?

Accepted Answer

$$K_m = [S] at$$ $$\frac{1}{2} V_{max}$$

Question 3

Which type of enzyme inhibition results in a decrease in $$V_{max}$$ but no change in $$K_m$$?

Accepted Answer

Noncompetitive inhibition

Question 4

A patient is prescribed a drug that covalently modifies a serine residue in the active site of an enzyme, permanently inactivating it. What type of inhibition is this?

Accepted Answer

Irreversible inhibition

Question 5

Which of the following is a characteristic of fat-soluble vitamins?

Accepted Answer

They are primarily stored in the liver.

Question 6

Which vitamin is ingested as a provitamin and is essential for vision and cell growth?

Accepted Answer

Vitamin A (retinol)

Question 7

Which of the following vitamins is required for the synthesis of prothrombin and is involved in blood clotting?

Accepted Answer

Vitamin K

Question 8

Which coenzyme is derived from niacin (vitamin B3) and is involved in oxidation-reduction reactions?

Accepted Answer

Nicotinamide adenine dinucleotide (NAD+)

Question 9

A blood test reveals elevated levels of creatine kinase (CK/CPK) and lactate dehydrogenase (LDH). What does this most likely indicate?

Accepted Answer

Heart attack (myocardial infarction)

Question 10

Which class of proteins is used in lateral flow assays (such as COVID-19 rapid tests) to bind to specific antigens?

Accepted Answer

Protective proteins (antibodies)

Question 11

Which regulatory mechanism involves the addition or removal of a phosphate group to activate or deactivate an enzyme?

Accepted Answer

Covalent modification

Question 12

Which vitamin deficiency is most likely to result in neural tube defects in newborns?

Accepted Answer

Vitamin B9 (folic acid)

Question 13

Which of the following statements about water-soluble vitamins is correct?

Accepted Answer

They often function as coenzymes.

Question 14

Which enzyme regulation mechanism involves the synthesis of an enzyme as an inactive precursor that must be cleaved to become active?

Accepted Answer

Zymogen activation

Question 15

Which of the following best describes the effect of a negative feedback mechanism in a metabolic pathway?

Accepted Answer

The end product inhibits the first enzyme, conserving resources.

Question 16

Which vitamin is required for collagen synthesis and acts as an antioxidant?

Accepted Answer

Vitamin C (ascorbic acid)

Question 17

Which of the following is true regarding the effect of uncompetitive inhibition on enzyme kinetics?

Accepted Answer

$$V_{max}$$ and $$K_m$$ both decrease by the same ratio.

Question 18

Which vitamin is synthesized in the skin upon exposure to sunlight and is essential for calcium absorption?

Accepted Answer

Vitamin D (calciferol)

Question 19

Which of the following best describes a coenzyme?

Accepted Answer

An organic molecule derived from vitamins that assists in enzyme catalysis

Question 20

Which vitamin deficiency is associated with the disease beriberi, characterized by nervous system deterioration and muscle weakness?

Accepted Answer

Vitamin B1 (thiamine)

Regulation of Enzyme Activity, Vitamins, and Diagnostic Testing in GOB Chemistry

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