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 represents 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 both $$V_{max}$$ and $$K_m$$ decreasing by the same ratio?

Accepted Answer

Uncompetitive inhibition

Question 4

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

Accepted Answer

Irreversible inhibition

Question 5

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

Accepted Answer

Covalent modification

Question 6

Why are vitamins classified as either fat-soluble or water-soluble?

Accepted Answer

Fat-soluble vitamins are stored in the liver, while water-soluble vitamins are not stored and must be regularly consumed.

Question 7

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

Accepted Answer

Vitamin A (retinol)

Question 8

Which of the following vitamins is NOT a coenzyme precursor?

Accepted Answer

Vitamin K (phylloquinone)

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

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

Accepted Answer

Antibodies (protective proteins)

Question 11

Which statement about water-soluble vitamins is correct?

Accepted Answer

They often serve as coenzyme precursors.

Question 12

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

Accepted Answer

Flavin adenine dinucleotide (FAD)

Question 13

A deficiency in which vitamin can lead to neural tube defects in developing embryos?

Accepted Answer

Vitamin B9 (folic acid)

Question 14

Which of the following best describes the function of an antioxidant?

Accepted Answer

It acts as a reducing agent, donating electrons to neutralize free radicals.

Question 15

Which vitamin is required for the synthesis of prothrombin, a key protein in blood clotting?

Accepted Answer

Vitamin K (phylloquinone)

Question 16

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

Accepted Answer

Zymogen activation

Question 17

Which of the following is a correct pairing of vitamin and its coenzyme form?

Accepted Answer

Vitamin B2 (riboflavin) – FAD

Question 18

Which of the following statements about feedback inhibition is correct?

Accepted Answer

It involves the end product of a pathway inhibiting the first enzyme.

Question 19

Which vitamin deficiency is associated with scurvy, characterized by poor collagen synthesis and bleeding gums?

Accepted Answer

Vitamin C (ascorbic acid)

Question 20

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

Accepted Answer

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

Lec 11 Regulation of Enzyme Activity, Vitamins, and Diagnostic Testing in GOB Chemistry

Study Guide - Practice Questions