Question 1

Which of the following best describes the 'fluid mosaic model' of the plasma membrane?

Accepted Answer

A dynamic structure with proteins and lipids that can move laterally within the bilayer.

Question 2

Which of the following molecules would most easily diffuse directly through a plasma membrane without the help of a transport protein?

Accepted Answer

Oxygen ($$O_2)$$

Question 3

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

Accepted Answer

Hypotonic

Question 4

Which of the following statements about cholesterol in animal cell membranes is CORRECT?

Accepted Answer

Cholesterol decreases membrane fluidity at high temperatures and increases it at low temperatures.

Question 5

Which experimental evidence supports the idea that membrane proteins can move laterally within the lipid bilayer?

Accepted Answer

Fusion of mouse and human cells labeled with different fluorescent antibodies, resulting in intermixing of membrane proteins.

Question 6

Which of the following is a function of membrane proteins?

Accepted Answer

Facilitating the movement of ions and molecules across the membrane.

Question 7

A patient has a genetic mutation that prevents the formation of LDL receptors on cell membranes. What is a likely consequence?

Accepted Answer

Increased levels of LDL cholesterol in the blood.

Question 8

Which of the following best explains why ions such as $$Na^+$$ and $$K^+$$ cannot easily cross the plasma membrane without assistance?

Accepted Answer

They are repelled by the hydrophobic core of the membrane due to their charge.

Question 9

Which of the following transport processes requires energy input from ATP?

Accepted Answer

Active transport via the sodium-potassium pump

Question 10

A plant cell is placed in a hypertonic solution. What is the most likely outcome?

Accepted Answer

The cell will undergo plasmolysis as water leaves.

Question 11

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

Accepted Answer

They allow water to move rapidly across the membrane via facilitated diffusion.

Question 12

Which of the following changes would increase the fluidity and permeability of a cell membrane at low temperature?

Accepted Answer

Increasing the proportion of unsaturated fatty acids in phospholipids.

Question 13

Which of the following is TRUE about the sidedness (asymmetry) of biological membranes?

Accepted Answer

Glycolipids are primarily found on the extracellular face of the plasma membrane.

Question 14

Which of the following is an example of secondary active transport?

Accepted Answer

Coupled movement of sucrose into the cell with protons ($$H^+) $$down their gradient.

Question 15

Which of the following statements about facilitated diffusion is CORRECT?

Accepted Answer

It uses transport proteins to move substances down their concentration gradient.

Question 16

Which of the following best describes the difference between channel proteins and carrier proteins?

Accepted Answer

Carrier proteins undergo conformational changes during transport, while channel proteins provide a continuous passage.

Question 17

Which of the following is a real-life example of receptor-mediated endocytosis?

Accepted Answer

Uptake of LDL cholesterol by cells

Question 18

Which of the following statements about the sodium-potassium pump is TRUE?

Accepted Answer

It moves three sodium ions out of the cell and two potassium ions into the cell.

Question 19

Which of the following best explains why plant cells do not burst when placed in a hypotonic solution?

Accepted Answer

They have a rigid cell wall that resists the influx of water.

Question 20

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

Accepted Answer

Synthesizing DNA for the cell

Membrane Structure and Function: Chapter 7 Study Guide

Study Guide - Practice Questions