Question 1

Cholesterol is a key molecule in animal cell membranes. Which of the following best explains its role in membrane fluidity at different temperatures?

Accepted Answer

Cholesterol decreases membrane fluidity at high temperatures and increases it at low temperatures by preventing tight packing of phospholipids.

Question 2

Which of the following statements about saturated and unsaturated fatty acids is correct?

Accepted Answer

Unsaturated fatty acids have double bonds that introduce kinks, preventing tight packing.

Question 3

A patient receives an intravenous solution that is hypotonic compared to their red blood cells. What is the most likely outcome for the patient's red blood cells?

Accepted Answer

The red blood cells will burst due to water influx.

Question 4

Facilitated diffusion of glucose into yeast cells occurs because:

Accepted Answer

Glucose moves down its concentration gradient via a transport protein.

Question 5

Which equation best represents the relationship between surface area ($$A) $$and volume ($$V) $$for a spherical cell?

Accepted Answer

$$A = 4 \pi r^2$

Question 6

Microvilli are important in the small intestine because they:

Accepted Answer

Increase the surface area for absorption.

Question 7

Which of the following best describes the difference between active transport and facilitated diffusion?

Accepted Answer

Active transport requires ATP, while facilitated diffusion does not.

Question 8

A drug is designed to inhibit a cancer cell's ability to pump out chemotherapy agents. What type of membrane transport is being targeted?

Accepted Answer

Active transport

Question 9

Which of the following molecules would be least likely to diffuse through a plasma membrane without a transport protein?

Accepted Answer

A large polar molecule

Question 10

Which statement about membrane lipids is true?

Accepted Answer

They contain a hydrophilic head and hydrophobic tail

Question 11

If a cell is placed in a solution with a lower solute concentration than its cytoplasm, what will happen?

Accepted Answer

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

Question 12

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

Accepted Answer

They have double bonds that introduce kinks, preventing tight packing of phospholipids.

Question 13

Which process requires energy input from the cell to move substances against their concentration gradient?

Accepted Answer

Active transport

Question 14

A researcher tests the permeability of a drug across three membranes: 0% saturated tails, 20% saturated, and 50% saturated. Which membrane will allow the most drug to pass through?

Accepted Answer

0% saturated tails

Question 15

Which of the following is a consequence of increasing the number of folds and grooves in a cell membrane?

Accepted Answer

Increased surface area for exchange of materials

Question 16

Which of the following statements about channel and carrier proteins is correct?

Accepted Answer

Channel proteins form pores in the membrane and undergo conformational changes to shuttle molecules across membranes.

Question 17

A trout moves from a warm environment into a cold environment. How will the saturation status of its membrane lipids change to maintain fluidity?

Accepted Answer

The hydrocarbons would become less saturated to increase the fluidity of the membrane.

Question 18

Which statement describes some aspect of facilitated diffusion?

Accepted Answer

Facilitated diffusion of solutes may occur through channel or transport proteins in the membrane.

Question 19

Which of the following is NOT a property of lipids?

Accepted Answer

Lipids contain less energy than proteins and carbohydrates.

Question 20

Which of the following best describes the difference between osmosis and simple diffusion?

Accepted Answer

Osmosis is the diffusion of water across a selectively permeable membrane.

Cell Membranes, Transport, and Lipids: General Biology Study Guide

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