Question 1

Which of the following best describes the amphipathic nature of phospholipids in the plasma membrane?

Accepted Answer

They have both a hydrophilic head and a hydrophobic tail.

Question 2

A red blood cell is placed in a hypertonic solution. What will most likely happen to the cell, and why?

Accepted Answer

It will shrink because water leaves the cell to balance solute concentrations.

Question 3

Which of the following statements about membrane fluidity is correct?

Accepted Answer

Increasing the proportion of unsaturated fatty acids increases membrane fluidity.

Question 4

Which type of membrane protein is most likely to function as a receptor for signal transduction?

Accepted Answer

Integral protein

Question 5

A cell is placed in a solution and water moves into the cell, causing it to swell. Which term best describes the solution?

Accepted Answer

Hypotonic

Question 6

Which of the following best explains why ions such as Na+ and K+ require transport proteins to cross the plasma membrane?

Accepted Answer

Ions are hydrophilic and cannot pass through the hydrophobic core of the lipid bilayer.

Question 7

Which process is responsible for the movement of oxygen (O$_2$) and carbon dioxide (CO$_2$) across the plasma membrane?

Accepted Answer

Simple diffusion

Question 8

What is the main function of glycoproteins and glycolipids on the cell membrane?

Accepted Answer

Cell-to-cell recognition

Question 9

Which of the following statements about facilitated diffusion is correct?

Accepted Answer

It requires specific transport proteins and moves substances down their concentration gradient.

Question 10

A plant cell is placed in a hypotonic solution. What is the physiological outcome, and what is the term for the pressure generated?

Accepted Answer

The cell becomes turgid due to turgor pressure.

Question 11

Which of the following best describes the role of cholesterol in the plasma membrane?

Accepted Answer

It acts as a fluidity buffer, preventing the membrane from becoming too rigid or too fluid.

Question 12

Which of the following is an example of active transport?

Accepted Answer

Sodium-potassium pump moving Na$^+$ out and K$^+$ into the cell using ATP.

Question 13

Which process allows a white blood cell to engulf a bacterium?

Accepted Answer

Phagocytosis

Question 14

What would happen to a freshwater protozoan if its contractile vacuole stopped functioning?

Accepted Answer

It would swell and possibly burst due to water influx.

Question 15

Which of the following best explains why facilitated diffusion reaches a maximum rate?

Accepted Answer

Carrier proteins become saturated and cannot transport molecules any faster.

Question 16

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

Accepted Answer

Synthesis of DNA

Question 17

A cell uses a cotransport protein to import glucose along with Na$^+$ ions. Which type of transport is this an example of?

Accepted Answer

Secondary active transport

Question 18

Which of the following best describes exocytosis?

Accepted Answer

The discharge of material from vesicles at the cell surface.

Question 19

Which of the following would most likely decrease the permeability of a cell membrane to water?

Accepted Answer

Decreasing the number of aquaporins in the membrane.

Question 20

Which of the following scenarios best illustrates the concept of selective permeability?

Accepted Answer

O$_2$ diffuses freely across the membrane, but Na$^+$ requires a channel protein.

Membrane Structure and Function: Study Notes

Study Guide - Practice Questions