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

Accepted Answer

Covalent modification

Question 6

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

Accepted Answer

Fat-soluble vitamins are primarily stored in the liver.

Question 7

Which vitamin is ingested in its provitamin form and is essential for vision and cell growth?

Accepted Answer

Vitamin A (retinol)

Question 8

Which water-soluble vitamin is also known as ascorbic acid and functions as an antioxidant and in collagen synthesis?

Accepted Answer

Vitamin C (ascorbic acid)

Question 9

Which coenzyme is derived from niacin and is involved in oxidation-reduction reactions?

Accepted Answer

Nicotinamide adenine dinucleotide (NAD$$^+)$$

Question 10

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 11

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 12

Which of the following is a true statement about coenzymes?

Accepted Answer

Coenzymes are organic molecules that assist enzymes in catalysis.

Question 13

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

Accepted Answer

Vitamin B1 (thiamine)

Question 14

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 15

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

Accepted Answer

A product of the pathway inhibits the first enzyme, conserving resources.

Question 16

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

Accepted Answer

Vitamin K

Question 17

Which water-soluble vitamin is essential for the transfer of one-carbon units in the synthesis of nucleic acids and prevention of neural tube defects?

Accepted Answer

Vitamin B9 (folic acid)

Question 18

Which of the following statements about enzyme affinity and $$K_m is $$correct?

Accepted Answer

A lower $$K_m$$ value indicates a higher affinity of the enzyme for its substrate.

Question 19

Which vitamin deficiency can result from strict vegetarian diets due to its primary sources being animal products, and leads to pernicious anemia?

Accepted Answer

Vitamin B12 (cobalamin)

Question 20

Which of the following best describes the role of an antioxidant in the body?

Accepted Answer

An antioxidant is a reducing agent that gets oxidized while reducing other molecules.

UM Exam 2 Lecture 11: Enzyme Regulation, Inhibition, and Vitamins: Key Concepts for GOB Chemistry

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