$$\Delta G = RT \ln \left( \frac{[C]_\text{out}}{[C]_\text{in}} \right) + zF\Delta V$$

Question 1

Which of the following best explains how cholesterol affects the fluidity of the plasma membrane at low temperatures?

Accepted Answer

Cholesterol increases membrane fluidity by preventing fatty acid tails from packing tightly.

Question 2

A cell is placed in a hypertonic solution. Which of the following best describes what will happen to an animal cell and a plant cell, respectively?

Accepted Answer

Animal cell will shrink; plant cell will undergo plasmolysis.

Question 3

Which of the following statements about facilitated diffusion is correct?

Accepted Answer

Facilitated diffusion is saturable and displays Michaelis-Menten kinetics.

Question 4

A mutation causes a transmembrane protein to have polar amino acids in its membrane-spanning region. What is the most likely consequence?

Accepted Answer

The protein will be unstable and may not properly embed in the membrane.

Question 5

Which equation correctly represents the change in free energy ($$\Delta G) $$for transport of a solute across a membrane?

Accepted Answer

$$\Delta G = RT \ln \left( \frac{[C]_	ext{out}}{[C]_	ext{in}} ight) + zF\Delta V$$

Question 6

Which of the following best describes the function of the Na$$^+/K$^+$$ ATPase pump?

Accepted Answer

It uses ATP to move Na$$^+$$ out and K$$^+$$ into the cell against their gradients.

Question 7

Which of the following is a characteristic of ABC transporters?

Accepted Answer

They use ATP hydrolysis to directly transport substrates across membranes.

Question 8

A cell is exposed to a toxin that inhibits the Signal Recognition Particle (SRP). Which process will be most directly affected?

Accepted Answer

Targeting of newly synthesized proteins to the endoplasmic reticulum.

Question 9

Which of the following best describes the difference between anterograde and retrograde transport in the Golgi apparatus?

Accepted Answer

Anterograde is movement from ER to Golgi; retrograde is movement from Golgi to ER.

Question 10

Which of the following is a specific type of endocytosis?

Accepted Answer

Receptor-mediated endocytosis

Question 11

Which of the following best describes the role of glycosylation in membrane proteins?

Accepted Answer

It aids in cell-cell recognition and protein stability.

Question 12

Which of the following statements about receptor affinity is correct?

Accepted Answer

A low K$$_d$$ indicates high receptor affinity for its ligand.

Question 13

Which of the following is NOT a function of the endoplasmic reticulum?

Accepted Answer

DNA replication

Question 14

Which of the following best describes the mechanism of signal amplification in a GPCR pathway?

Accepted Answer

One ligand activates one receptor, which activates many G proteins, leading to many second messengers.

Question 15

Which molecule acts as a second messenger in the pathway involving phospholipase C?

Accepted Answer

IP$$_3$$

Question 16

Which of the following best describes the role of calcium ions in cell signaling?

Accepted Answer

Calcium ions act as a second messenger, triggering various cellular responses.

Question 17

Which of the following is an example of endocrine signaling?

Accepted Answer

A hormone released by the pancreas traveling through the bloodstream to affect distant cells.

Question 18

Which of the following best describes crosstalk in cell signaling pathways?

Accepted Answer

Crosstalk refers to the integration of signals from different pathways.

Question 19

Which of the following best describes the function of a scaffold protein in cell signaling?

Accepted Answer

Scaffold proteins organize and localize signaling components to enhance efficiency.

Cell Biology Study Guide: Membranes, Transport, Endomembrane System, and Signal Transduction

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