Q: Which equation best represents the calculation of membrane potential ($$V_m) $$using the Nernst equation for a single ion?

$$V_m = \frac{RT}{zF} \ln \left( \frac{[\text{ion}]_{\text{outside}}}{[\text{ion}]_{\text{inside}}} \right)$$

Question 1

Which statement best describes the fluid mosaic model of the cell membrane?

Accepted Answer

The membrane is a dynamic structure with proteins embedded in or attached to a fluid phospholipid bilayer.

Question 2

Which of the following factors increases membrane fluidity?

Accepted Answer

A higher proportion of unsaturated fatty acids in phospholipids.

Question 3

A red blood cell is placed in a hypotonic solution. What will happen to the cell?

Accepted Answer

Water will enter the cell, causing it to swell and possibly burst.

Question 4

Which equation best represents the calculation of membrane potential ($$V_m) $$using the Nernst equation for a single ion?

Accepted Answer

$$V_m = \frac{RT}{zF} \ln \left( \frac{[	ext{ion}]_{	ext{outside}}}{[	ext{ion}]_{	ext{inside}}} ight)$$

Question 5

Which of the following is an example of active transport?

Accepted Answer

Sodium-potassium pump transporting Na$$^+$$ out and K$$^+$$ into the cell against their concentration gradients.

Question 6

Which process requires energy input from the cell and moves large particles into the cell?

Accepted Answer

Phagocytosis

Question 7

A cell is placed in a solution with a higher solute concentration than its cytoplasm. What type of solution is this, and what is the expected effect on the cell?

Accepted Answer

Hypertonic; the cell will lose water and shrink.

Question 8

Which membrane protein is responsible for rapid water transport across the cell membrane?

Accepted Answer

Aquaporin

Question 9

Which of the following best describes facilitated diffusion?

Accepted Answer

Movement of molecules down their concentration gradient through a membrane protein without energy input.

Question 10

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

Accepted Answer

Synthesis of ATP.

Question 11

Which type of endocytosis involves the cell engulfing liquid droplets?

Accepted Answer

Pinocytosis

Question 12

Cholesterol acts as a temperature buffer in the cell membrane. What is its effect at high temperatures?

Accepted Answer

It decreases membrane fluidity.

Question 13

Which of the following best explains why the sodium-potassium pump is considered an electrogenic pump?

Accepted Answer

It creates a net charge difference across the membrane by moving more Na$$^+$$ out than K$$^+ in.$$

Question 14

Which of the following is true about simple diffusion?

Accepted Answer

It does not require energy and moves molecules down their concentration gradient.

Question 15

Which process is responsible for the export of proteins from the cell?

Accepted Answer

Exocytosis

Question 16

A patient with cystic fibrosis has a defective CFTR protein. What is the primary consequence at the cellular level?

Accepted Answer

Reduced facilitated diffusion of chloride ions across the membrane.

Question 17

Which of the following best describes receptor-mediated endocytosis?

Accepted Answer

The cell uses specific membrane receptors to selectively take in certain molecules.

Question 18

Which of the following is a transmembrane protein function that is critical for immune system recognition?

Accepted Answer

Cell-cell recognition via glycoproteins.

Question 19

If a cell's membrane becomes less permeable to water, which process will be most directly affected?

Accepted Answer

Osmosis

Question 20

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.

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