Question 1

Which component of the cell membrane is primarily responsible for its selective permeability to ions and polar molecules?

Accepted Answer

Integral membrane proteins

Question 2

A cell is placed in a cold environment. To maintain membrane fluidity, which change is most likely to occur in the phospholipid composition?

Accepted Answer

Increase the proportion of unsaturated fatty acids

Question 3

Which of the following molecules can pass directly through the lipid bilayer of the plasma membrane without the aid of a transport protein?

Accepted Answer

CO$$_2$$

Question 4

What is the primary function of glycoproteins in the cell membrane?

Accepted Answer

Act as cell surface markers for recognition

Question 5

Which equation best describes the movement of molecules during diffusion across a membrane?

Accepted Answer

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

Question 6

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

Accepted Answer

It will shrivel due to water loss

Question 7

Which of the following statements about cholesterol in the cell membrane is TRUE?

Accepted Answer

Cholesterol acts as a temperature buffer, stabilizing fluidity

Question 8

Which process requires energy input from ATP?

Accepted Answer

Active transport of Na$$^+$$ ions via the Na$$^+/K$^+$$ pump

Question 9

What is the main difference between integral and peripheral membrane proteins?

Accepted Answer

Integral proteins are embedded in the membrane, peripheral proteins are loosely associated

Question 10

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

Accepted Answer

A double layer of phospholipids with proteins and other molecules floating within

Question 11

Which type of transport protein changes shape to move a solute across the membrane?

Accepted Answer

Carrier protein

Question 12

During endocytosis, which structure is formed to bring substances into the cell?

Accepted Answer

Vesicle

Question 13

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

Accepted Answer

Synthesis of phospholipids

Question 14

A cell needs to import a large quantity of a specific molecule. Which process is most likely used?

Accepted Answer

Receptor-mediated endocytosis

Question 15

Which of the following best explains why water can cross the cell membrane despite being polar?

Accepted Answer

Water uses aquaporin channels for facilitated diffusion

Question 16

Which equation represents the relationship between osmotic pressure and solute concentration?

Accepted Answer

$$\Pi = iMRT$$

Question 17

Which of the following would increase the viscosity of a cell membrane?

Accepted Answer

Increasing the proportion of saturated fatty acids

Question 18

Which of the following is TRUE about the asymmetry of the cell membrane?

Accepted Answer

The outer and inner leaflets have different components and functions

Question 19

Which process is responsible for the secretion of large molecules from a cell?

Accepted Answer

Exocytosis

Question 20

Which of the following best describes the role of the Na$$^+/K$^+$$ pump in the cell membrane?

Accepted Answer

It pumps sodium and potassium ions against their concentration gradients using ATP

Cell Membrane Structure and Function: General Biology Study Notes

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