Question 1

Which of the following best describes the role of cholesterol in the plasma membrane of animal cells?

Accepted Answer

It increases membrane fluidity at low temperatures and decreases fluidity at high temperatures.

Question 2

A red blood cell is placed in a hypotonic solution. What is the most likely outcome, and why?

Accepted Answer

The cell will swell and may burst because water will move into the cell.

Question 3

Which of the following transport processes requires energy directly from ATP hydrolysis?

Accepted Answer

Active transport via the sodium-potassium pump

Question 4

A plant cell in a hypertonic environment will most likely experience which of the following?

Accepted Answer

Undergo plasmolysis as water leaves the cell

Question 5

Which of the following statements about enzymes is correct?

Accepted Answer

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

Question 6

Given the Gibb’s Free Energy equation $$\Delta G = \Delta H - T\Delta S$$, which of the following conditions would always result in a spontaneous reaction?

Accepted Answer

$$\Delta H  0$$

Question 7

Which of the following best explains why ATP is considered the 'energy currency' of the cell?

Accepted Answer

ATP hydrolysis releases energy that can be coupled to endergonic reactions.

Question 8

During glycolysis, what are the net products generated from one molecule of glucose?

Accepted Answer

2 ATP, 2 NADH, and 2 pyruvate

Question 9

Which of the following statements about the electron transport chain (ETC) in mitochondria is correct?

Accepted Answer

Oxygen serves as the final electron acceptor, forming water.

Question 10

A patient’s muscle cells are deprived of oxygen during intense exercise. Which process allows ATP production to continue, and what is the main byproduct?

Accepted Answer

Fermentation; lactic acid

Question 11

Which of the following best describes the difference between catabolic and anabolic pathways?

Accepted Answer

Catabolic pathways release energy by breaking down molecules; anabolic pathways consume energy to build molecules.

Question 12

Which of the following is an example of feedback inhibition in metabolic pathways?

Accepted Answer

A product of a pathway binds to an enzyme earlier in the pathway, inhibiting its activity.

Question 13

If a cell is placed in a solution and water moves into the cell, causing it to swell, what can you infer about the tonicity of the solution relative to the cell?

Accepted Answer

The solution is hypotonic to the cell.

Question 14

Which of the following best describes the process of chemiosmosis in cellular respiration?

Accepted Answer

The movement of protons ($$H^+) $$down their gradient through ATP synthase to produce ATP.

Question 15

Which of the following is NOT a function of membrane proteins?

Accepted Answer

Synthesis of phospholipids

Question 16

A scientist measures the entropy ($$S) $$and enthalpy ($$H) $$changes of a reaction at constant temperature ($$T). If$$ $$\Delta H = +10 kJ/$$mol and $$\Delta S = +0.05 kJ/($$mol·K), at what temperature (in Kelvin) will the reaction become spontaneous?

Accepted Answer

$$T \u003e 200 K$$

Question 17

Which of the following statements about oxidative phosphorylation is correct?

Accepted Answer

It produces ATP using the energy from a proton gradient across the inner mitochondrial membrane.

Question 18

Which of the following best explains why FADH2 produces less ATP than NADH during cellular respiration?

Accepted Answer

FADH2 donates electrons at a later point in the electron transport chain, resulting in fewer protons pumped across the membrane.

Question 19

Which of the following processes is an example of receptor-mediated endocytosis?

Accepted Answer

A cell taking in cholesterol via LDL particles binding to specific membrane receptors.

Question 20

Which of the following statements about fermentation is correct?

Accepted Answer

Fermentation allows glycolysis to continue by regenerating NAD+.

Principles of Biology Exam III Review: Cell Membranes, Energy & Enzymes, Cellular Respiration

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