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

Question 1

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

Accepted Answer

Proteins are embedded in a lipid bilayer, allowing lateral movement and flexibility.

Question 2

How does cholesterol affect membrane fluidity at different temperatures?

Accepted Answer

Cholesterol acts as a buffer, stabilizing membrane fluidity by decreasing fluidity at high temperatures and increasing it at low temperatures.

Question 3

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

Accepted Answer

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

Question 4

Which type of membrane protein is primarily responsible for transporting ions against their concentration gradient?

Accepted Answer

Electrogenic pumps

Question 5

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 6

Which process requires energy input from the cell to move substances across the membrane?

Accepted Answer

Active transport

Question 7

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

Accepted Answer

Disrupted chloride ion transport, leading to thick mucus secretions

Question 8

Which of the following best describes receptor-mediated endocytosis?

Accepted Answer

The cell uses specific receptors to internalize targeted molecules from the extracellular environment.

Question 9

Which scenario best illustrates the function of aquaporins in a kidney cell?

Accepted Answer

Rapid movement of water across the membrane during urine concentration.

Question 10

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

Accepted Answer

Synthesis of ATP from glucose

Question 11

A plant cell is placed in a hypertonic solution. What will happen to the cell?

Accepted Answer

Water will leave the cell, causing the cell membrane to pull away from the cell wall (plasmolysis).

Question 12

Which type of transport is used by the sodium-potassium pump in animal cells?

Accepted Answer

Active transport

Question 13

Which of the following best explains why unsaturated fatty acids increase membrane fluidity?

Accepted Answer

They introduce kinks in the fatty acid tails, preventing tight packing.

Question 14

Which process is responsible for the movement of oxygen from the lungs into the blood?

Accepted Answer

Simple diffusion

Question 15

A cell uses $$2 	ext{Na}^+$$ ions to move $$1 	ext{K}^+$$ ion against its concentration gradient. Which type of transport is this?

Accepted Answer

Antiport

Question 16

Which of the following is a correct sequence for bulk transport processes?

Accepted Answer

Endocytosis → Pinocytosis → Receptor-mediated endocytosis

Question 17

Which membrane protein is most likely to be involved in cell-cell recognition?

Accepted Answer

Glycoprotein

Question 18

A neuron maintains a resting membrane potential of $$-70\ 	ext{mV}. $$What is the primary cause of this negative potential?

Accepted Answer

Greater permeability of the membrane to potassium ions than to sodium ions

Question 19

Which of the following best describes facilitated diffusion?

Accepted Answer

Movement of molecules down their concentration gradient via channel or carrier proteins without energy input

Question 20

Which scenario best illustrates the difference between phagocytosis and pinocytosis?

Accepted Answer

A white blood cell engulfs a bacterium (phagocytosis), while an intestinal cell absorbs dissolved nutrients (pinocytosis).

Membrane Structure and Function: Study Guide for General Biology

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