Question 1

Which component of the cytoskeleton is primarily responsible for resisting mechanical stress and maintaining cell shape in animal cells?

Accepted Answer

Intermediate filaments

Question 2

A unicellular organism uses many short hair-like structures to move through its environment. What are these structures called, and what is their main difference from flagella?

Accepted Answer

Cilia; they are shorter and more numerous

Question 3

Despite being mostly water, the cytosol of a cell is 'gooey.' What is the main reason for this property?

Accepted Answer

High concentration of proteins, nutrients, and other solutes

Question 4

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

Accepted Answer

Phosphate heads are hydrophilic and lipid tails are hydrophobic

Question 5

According to the fluid mosaic model, what is the main reason phospholipids can move laterally within the membrane?

Accepted Answer

They are held together by hydrophobic interactions, not by strong bonds

Question 6

What role does cholesterol play in the cell membrane at varying temperatures?

Accepted Answer

It acts as a fluidity buffer, limiting movement at high temperatures and lowering the temperature of solidification

Question 7

A cell is placed in a hypertonic solution. What will happen to an animal cell and a plant cell, respectively?

Accepted Answer

Animal cell will shrivel; plant cell will become plasmolyzed

Question 8

Which equation correctly represents the concentration ($C$) of a solution in terms of mass of solute ($m$) and total volume of solution ($V$)?

Accepted Answer

$C = \frac{m}{V}$

Question 9

Why is it important that human blood is isotonic to the cytoplasm of our cells?

Accepted Answer

It prevents excessive uptake or loss of water by cells, maintaining cell integrity

Question 10

Which type of membrane protein is most likely to be involved in signal transduction?

Accepted Answer

Integral protein

Question 11

A cell needs to import glucose, a large polar molecule, from the extracellular environment. Which transport mechanism is most likely used?

Accepted Answer

Facilitated diffusion via a carrier protein

Question 12

Which of the following best describes the direction of water movement during osmosis?

Accepted Answer

From high concentration to low concentration

Question 13

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

Accepted Answer

Passive transport moves particles down their concentration gradient, active transport moves particles against their concentration gradient

Question 14

Which of the following is a consequence of decreasing the fluidity of the cell membrane?

Accepted Answer

Decreased permeability, potentially disrupting cellular homeostasis

Question 15

A plant cell is placed in distilled water. What prevents it from bursting?

Accepted Answer

Cell wall

Question 16

Which process involves the engulfment of large particles by the cell membrane to form a vesicle?

Accepted Answer

Phagocytosis

Question 17

What is the main function of aquaporins in the cell membrane?

Accepted Answer

Facilitate the movement of water across the membrane

Question 18

Which of the following best explains why small cells are more efficient at transporting materials than large cells?

Accepted Answer

They have a higher surface area to volume ratio

Question 19

A cell uses a sodium-potassium pump to maintain its membrane potential. Which equation best describes the electrochemical gradient ($\Delta G$) for ion movement?

Accepted Answer

$\Delta G = RT \ln \left( \frac{[	ext{ion}]_{	ext{outside}}}{[	ext{ion}]_{	ext{inside}}} ight) + zF\Delta \Psi$

Question 20

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

Accepted Answer

DNA replication

Cell Structure and Membrane Transport: Key Concepts in Cell Biology

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