Question 1

Which of the following statements correctly describes the role of NAD+ in cellular metabolism?

Accepted Answer

NAD+ is reduced to NADH during catabolic reactions, accepting electrons and protons.

Question 2

According to the table, when a substance is oxidized, what happens to its electron count and how does it behave?

Accepted Answer

It loses electrons and acts as a reductant.

Question 3

Ibuprofen inhibits the enzyme cyclooxygenase by which mechanism?

Accepted Answer

Competitive inhibition, directly competing with arachidonic acid for the active site.

Question 4

Which component of the plasma membrane is primarily responsible for membrane fluidity and stability?

Accepted Answer

Cholesterol

Question 5

What is the main difference between saturated and unsaturated fatty acids in phospholipids?

Accepted Answer

Unsaturated fatty acids contain one or more double bonds, causing kinks in the tail.

Question 6

Which organelle membrane contains the highest proportion of cardiolipin, according to the lipid composition chart?

Accepted Answer

Inner mitochondrial membrane

Question 7

Which type of membrane transport is illustrated by the movement of glucose through GLUT transporters?

Accepted Answer

Facilitated diffusion

Question 8

In cotransport systems, what is the main difference between symport and antiport mechanisms?

Accepted Answer

Symport moves two molecules in the same direction, antiport moves them in opposite directions.

Question 9

Why is sucralose not metabolized by the human body, unlike sucrose?

Accepted Answer

Sucralose contains chlorine atoms, making it resistant to enzymatic hydrolysis.

Question 10

Which glycosidic bond is responsible for the branching in amylopectin?

Accepted Answer

$$\alpha-1$$,6-glycosidic bond

Question 11

Which polysaccharide is composed of glucose units linked exclusively by $$\beta-1$$,4-glycosidic bonds and is not metabolized by humans?

Accepted Answer

Cellulose

Question 12

During the digestion of starch, which enzyme is responsible for breaking $$\alpha-1$$,4-glycosidic bonds?

Accepted Answer

Amylase

Question 13

Which GLUT transporter is insulin-dependent and primarily found in skeletal muscle and adipose tissue?

Accepted Answer

GLUT4

Question 14

Based on the Michaelis-Menten graph, which GLUT transporter has the highest affinity for glucose?

Accepted Answer

GLUT1 and GLUT3

Question 15

Which equation describes the relationship between Gibbs free energy, enthalpy, and entropy?

Accepted Answer

$$\Delta G = \Delta H - T \Delta S$$

Question 16

A reaction is considered spontaneous if $$\Delta G is$$:

Accepted Answer

Negative

Question 17

Which of the following best describes the function of coenzymes like NAD and FAD in metabolic reactions?

Accepted Answer

They transfer electrons during redox reactions.

Question 18

Which of the following statements about enzyme inhibition is correct?

Accepted Answer

Non-competitive inhibitors decrease $$V_{max}$$ but do not affect $$K_m.$$

Question 19

Which transport mechanism is used by SGLT1 for glucose absorption in the intestine?

Accepted Answer

Active transport (secondary)

Biochemistry Study Guide: Metabolism, Enzymes, Membranes, and Carbohydrates

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