Q: Which equation correctly represents the net reaction of ATP hydrolysis?

$$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{ADP} + \mathrm{P}_i + \text{energy}$$

Q: Which equation represents the conversion of pyruvate to Acetyl-CoA by pyruvate dehydrogenase?

$$\text{Pyruvate} + \text{CoA} + \text{NAD}^+ \rightarrow \text{Acetyl-CoA} + \text{CO}_2 + \text{NADH}$$

Question 1

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

Accepted Answer

Cholesterol increases membrane fluidity at high temperatures and decreases it at low temperatures.

Question 2

A researcher is studying the movement of glucose across a cell membrane. Which transport mechanism is most likely involved, and what is the driving force?

Accepted Answer

Facilitated diffusion; driven by the concentration gradient of glucose.

Question 3

Which equation correctly represents the net reaction of ATP hydrolysis?

Accepted Answer

$$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} ightarrow \mathrm{ADP} + \mathrm{P}_i + 	ext{energy}$$

Question 4

A mutation causes a defect in the enzyme that converts pyruvate to Acetyl-CoA. Which metabolic pathway would be directly affected?

Accepted Answer

The TCA (Krebs) cycle

Question 5

Which of the following statements about the sodium-potassium pump is correct?

Accepted Answer

It moves 3 Na$$^+$$ ions out of the cell and 2 K$$^+$$ ions into the cell per ATP hydrolyzed.

Question 6

During oxidative phosphorylation, which process couples the electron transport chain to ATP synthesis?

Accepted Answer

The proton gradient across the inner mitochondrial membrane

Question 7

A patient with Tay-Sachs disease has a deficiency in a lysosomal enzyme. What is the primary cellular consequence?

Accepted Answer

Accumulation of undigested lipids in lysosomes

Question 8

Which of the following best explains why phospholipids form bilayers in aqueous environments?

Accepted Answer

Their hydrophilic heads interact with water while hydrophobic tails avoid water.

Question 9

Which organelle is primarily responsible for detoxifying drugs and synthesizing lipids in liver cells?

Accepted Answer

Smooth Endoplasmic Reticulum

Question 10

A cell is placed in a solution with a lower solute concentration than its cytoplasm. What will happen to the cell?

Accepted Answer

Water will enter the cell, causing it to swell.

Question 11

Which of the following is a function of the Golgi apparatus?

Accepted Answer

Modification and sorting of proteins for secretion

Question 12

Which equation represents the conversion of pyruvate to Acetyl-CoA by pyruvate dehydrogenase?

Accepted Answer

$$	ext{Pyruvate} + 	ext{CoA} + 	ext{NAD}^+ ightarrow 	ext{Acetyl-CoA} + 	ext{CO}_2 + 	ext{NADH}$$

Question 13

Which of the following statements about photosystem II (PSII) is correct?

Accepted Answer

PSII is responsible for splitting water and generating oxygen during photosynthesis.

Question 14

A cell is exposed to cyanide, which inhibits cytochrome c oxidase in the electron transport chain. What is the immediate effect?

Accepted Answer

ATP synthesis via oxidative phosphorylation stops.

Question 15

Which of the following best describes the function of peroxisomes?

Accepted Answer

Breakdown of hydrogen peroxide via catalase

Question 16

Which process is responsible for the movement of electrons from NADH to oxygen in mitochondria?

Accepted Answer

Electron transport chain

Question 17

Which of the following is a key regulatory enzyme in glycolysis?

Accepted Answer

Phosphofructokinase

Question 18

A cell is unable to synthesize NADPH. Which process would be most directly affected?

Accepted Answer

The Calvin cycle in photosynthesis

Question 19

Which of the following best explains the difference between simple diffusion and facilitated diffusion?

Accepted Answer

Facilitated diffusion requires membrane proteins, while simple diffusion does not.

Question 20

Which of the following is true regarding the absorption spectrum of chlorophyll in photosystems?

Accepted Answer

PSI contains chlorophyll P700, which absorbs light at 700 nm.

Cell Biology Midterm 2 Review Guide: Membranes, Transport, Endomembrane System, Metabolism, and Photosynthesis

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