Question 1

Which of the following best explains why water is an effective solvent for biological molecules?

Accepted Answer

Water forms hydrogen bonds with polar molecules, allowing it to dissolve many substances.

Question 2

Which intermolecular force is primarily responsible for the secondary structure of proteins?

Accepted Answer

Hydrogen bonds

Question 3

A cell is exposed to a toxin that inhibits ATP synthase. Which process will be directly affected?

Accepted Answer

Oxidative phosphorylation

Question 4

Which equation correctly represents the relationship between Gibbs free energy ($$\Delta G$$), enthalpy ($$\Delta H$$), and entropy ($$\Delta S) at $$temperature $$T$$?

Accepted Answer

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

Question 5

Which of the following statements about enzymes is TRUE?

Accepted Answer

Enzymes lower the activation energy, increasing the rate of reaction.

Question 6

A mutation changes a hydrophobic amino acid in the core of a protein to a charged amino acid. What is the most likely effect?

Accepted Answer

The protein may misfold or lose its function due to disruption of hydrophobic interactions.

Question 7

Which of the following is NOT a product of glycolysis?

Accepted Answer

FADH$$_2$$

Question 8

During cellular respiration, which molecule acts as the final electron acceptor in the electron transport chain?

Accepted Answer

O$$_2$$

Question 9

Which of the following best describes the induced-fit model of enzyme activity?

Accepted Answer

The enzyme changes shape upon substrate binding to better accommodate the substrate.

Question 10

Which of the following amino acids is polar and uncharged at physiological pH?

Accepted Answer

Serine

Question 11

If the $$\Delta G of a $$reaction is negative, what does this indicate about the reaction?

Accepted Answer

The reaction is spontaneous and can proceed without energy input.

Question 12

Which of the following statements about ATP is correct?

Accepted Answer

ATP hydrolysis releases energy due to the repulsion between negatively charged phosphate groups.

Question 13

Which process occurs in the absence of oxygen and results in the production of lactate in muscle cells?

Accepted Answer

Lactic acid fermentation

Question 14

Which of the following is a correct description of substrate-level phosphorylation?

Accepted Answer

ATP is generated directly from the transfer of a phosphate group from a substrate to ADP.

Question 15

Which of the following is TRUE about allosteric inhibition of enzymes?

Accepted Answer

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

Question 16

Which of the following is a function of NADH in cellular respiration?

Accepted Answer

Transfers electrons to the electron transport chain for ATP production.

Question 17

Which of the following best describes the role of coenzyme A (CoA) in cellular metabolism?

Accepted Answer

CoA binds to acetyl groups, forming acetyl-CoA, which enters the citric acid cycle.

Question 18

Which of the following is the correct sequence of events in a catalytic reaction involving an enzyme?

Accepted Answer

Substrate binding, transition state formation, product release

Question 19

A patient is diagnosed with a genetic disorder that affects the function of the pyruvate dehydrogenase complex. Which metabolic pathway will be directly impaired?

Accepted Answer

Citric acid cycle (Krebs cycle)

Question 20

Which of the following best explains why the phosphoanhydride bonds in ATP are considered 'high energy'?

Accepted Answer

Their hydrolysis releases energy due to electrostatic repulsion and resonance stabilization of products.

Cell Biology Core Concepts: Chemistry, Energetics, Proteins, and Enzymes

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