$$E = \frac{RT}{zF} \ln \frac{[\text{ion outside}]}{[\text{ion inside}]}$$

Question 1

Which of the following best describes the Fluid Mosaic Model of the cell membrane?

Accepted Answer

A dynamic bilayer of phospholipids with proteins and other molecules embedded and able to move laterally.

Question 2

Which organelle is thought to have originated via endosymbiosis, as evidenced by its double membrane and own DNA?

Accepted Answer

Mitochondrion

Question 3

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

Accepted Answer

It will swell as water enters the cell.

Question 4

Which of the following is a function of membrane proteins?

Accepted Answer

Acting as channels, receptors, and enzymes within the membrane.

Question 5

What is the main difference between passive and active transport across the cell membrane?

Accepted Answer

Active transport requires energy input, while passive transport does not.

Question 6

Which equation best represents the Nernst equation for membrane potential?

Accepted Answer

$$E = \frac{RT}{zF} \ln \frac{[	ext{ion outside}]}{[	ext{ion inside}]}$$

Question 7

Which of the following statements about prokaryotic cells is correct?

Accepted Answer

Their metabolic processes occur on the plasma membrane.

Question 8

Which type of lipid is most abundant in the plasma membrane?

Accepted Answer

Phospholipids

Question 9

A mutation causes a cell to lack aquaporin proteins. What is the most likely consequence?

Accepted Answer

The cell will have reduced water permeability.

Question 10

Which process involves the cell membrane engulfing extracellular material to bring it into the cell?

Accepted Answer

Endocytosis

Question 11

Which of the following best explains why cholesterol is important in animal cell membranes?

Accepted Answer

It stabilizes membrane fluidity across temperature changes.

Question 12

Which of the following is true about the selective permeability of the cell membrane?

Accepted Answer

Only water and small nonpolar molecules can diffuse directly through the bilayer.

Question 13

Which of the following is a real-world example of secondary active transport in cells?

Accepted Answer

Glucose uptake in intestinal cells via sodium-glucose symporter.

Question 14

Which of the following best describes the role of glycoproteins in the cell membrane?

Accepted Answer

They serve as recognition sites for cell-cell interactions.

Question 15

Which equation describes the rate of simple diffusion across a membrane according to Fick's Law?

Accepted Answer

$$J = -D \frac{dC}{dx}$$

Question 16

Which of the following is NOT a function of the endomembrane system?

Accepted Answer

Energy production via oxidative phosphorylation

Question 17

A patient has a genetic defect in the sodium-potassium pump. Which of the following cellular consequences is most likely?

Accepted Answer

Loss of membrane potential and inability to maintain ion gradients.

Question 18

Which of the following statements about lipid rafts is correct?

Accepted Answer

They are specialized microdomains involved in specific transport and signaling.

Question 19

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 it.

Question 20

Which process is responsible for the movement of large particles, such as bacteria, into a cell?

Accepted Answer

Phagocytosis

Cell Membranes: Structure and Function – Study Notes

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