Question 1

Which component of the fluid mosaic model is primarily responsible for the selective permeability of cellular membranes?

Accepted Answer

Phospholipid bilayer

Question 2

A red blood cell is placed in a hypotonic solution. What will happen to the cell, and which principle explains this?

Accepted Answer

It will swell and possibly burst due to water influx, explained by osmosis

Question 3

Which equation best describes the net movement of solutes during simple diffusion across a membrane?

Accepted Answer

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

Question 4

Which type of membrane protein is covalently attached to fatty acids and is not embedded within the lipid bilayer?

Accepted Answer

Lipid-anchored protein

Question 5

A nerve cell uses the sodium-potassium pump to maintain ion gradients. Which equation represents the energy required for this active transport?

Accepted Answer

$\Delta G = RT \ln \left( \frac{[Na^+]_{out}}{[Na^+]_{in}} \right) + zF\Delta \Psi$

Question 6

Which of the following is NOT a function of cellular membranes as listed in Table 5.1?

Accepted Answer

Synthesis of DNA

Question 7

Which process requires a transport protein and moves molecules down their concentration gradient without energy input?

Accepted Answer

Facilitated diffusion

Question 8

Which type of cell junction is responsible for preventing the leakage of extracellular fluid between adjacent animal cells?

Accepted Answer

Tight junctions

Question 9

A glucose molecule enters a cell via a transporter protein. If the external glucose concentration is higher than the internal, which transport mechanism is most likely involved?

Accepted Answer

Facilitated diffusion

Question 10

Which of the following best describes the role of integrins in cellular membranes?

Accepted Answer

They connect cells to the extracellular matrix and transmit signals

Question 11

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

Accepted Answer

Uptake of LDL cholesterol by cells

Question 12

Which equation describes the osmotic pressure exerted by solutes across a semipermeable membrane?

Accepted Answer

$\Pi = iMRT$

Question 13

Which of the following statements about the extracellular matrix (ECM) is correct?

Accepted Answer

Fibronectin connects cells to the ECM and helps organize its components

Question 14

Which type of active transport directly uses ATP to move ions against their concentration gradient?

Accepted Answer

Primary active transport

Question 15

Which of the following best explains why ions such as Na	extsuperscript{+} and K	extsuperscript{+} cannot easily cross the lipid bilayer by simple diffusion?

Accepted Answer

They are hydrophilic and charged, making them incompatible with the hydrophobic core

Question 16

Which cell junction allows for the direct passage of ions and small molecules between adjacent animal cells?

Accepted Answer

Gap junctions

Question 17

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

Accepted Answer

The cell will lose water and undergo plasmolysis

Question 18

Which of the following is a function of cadherins in cellular membranes?

Accepted Answer

Facilitating homotypic cell adhesion

Question 19

Which process is used by immune cells to engulf and destroy pathogens?

Accepted Answer

Phagocytosis

Question 20

Which of the following best describes the role of aquaporins in cellular membranes?

Accepted Answer

They facilitate rapid passive movement of water across the membrane

Cellular Membranes: Structure, Function, and Composition

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