$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{ADP} + \mathrm{P}_i + \text{energy}$

Question 1

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

Accepted Answer

Phospholipids have both hydrophilic and hydrophobic regions, with hydrophobic tails facing inward and hydrophilic heads facing outward toward water.

Question 2

According to the fluid mosaic model, which statement is correct about membrane structure?

Accepted Answer

The membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids.

Question 3

How does cholesterol affect membrane fluidity at different temperatures in animal cells?

Accepted Answer

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

Question 4

A plant cell is placed in a hypotonic solution. What will happen to the cell?

Accepted Answer

The cell will gain water, swell, and become turgid.

Question 5

Which type of membrane protein is most likely to be involved in cell recognition and immune response?

Accepted Answer

Glycoproteins

Question 6

Which equation best represents the hydrolysis of ATP during active transport?

Accepted Answer

$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} ightarrow \mathrm{ADP} + \mathrm{P}_i + 	ext{energy}$

Question 7

Which of the following molecules can most easily diffuse through the lipid bilayer without a transport protein?

Accepted Answer

Oxygen ($\mathrm{O}_2$)

Question 8

A red blood cell is placed in a hypertonic solution. Predict what will happen to the cell and explain why.

Accepted Answer

Water will leave the cell, causing it to shrink and shrivel.

Question 9

Which process is responsible for the uptake of cholesterol into animal cells?

Accepted Answer

Receptor-mediated endocytosis

Question 10

Which of the following statements about facilitated diffusion is correct?

Accepted Answer

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

Question 11

What is the main function of the sodium-potassium pump in animal cells?

Accepted Answer

To maintain membrane potential by pumping $\mathrm{Na}^+$ out and $\mathrm{K}^+$ in

Question 12

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

Accepted Answer

Water moves from an area of lower solute concentration to higher solute concentration.

Question 13

Which type of transport protein is responsible for creating a hydrophilic channel for ions to pass through the membrane?

Accepted Answer

Channel protein

Question 14

A cell uses a cotransporter to move glucose into the cell along with sodium ions. Which type of transport is this an example of?

Accepted Answer

Coupled transport (secondary active transport)

Question 15

Which equation best describes the electrochemical gradient for an ion across a membrane?

Accepted Answer

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

Question 16

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

Accepted Answer

Synthesis of phospholipids

Question 17

Which type of endocytosis is most specific for the uptake of particular molecules?

Accepted Answer

Receptor-mediated endocytosis

Question 18

Why do membranes rich in unsaturated fatty acids remain more fluid at lower temperatures?

Accepted Answer

Unsaturated fatty acids have kinks in their tails, preventing tight packing.

Question 19

Which of the following best explains why glucose cannot easily cross the plasma membrane without a transport protein?

Accepted Answer

Glucose is a large, polar molecule.

Question 20

Which process is used by secretory cells in the pancreas to release insulin into the bloodstream?

Accepted Answer

Exocytosis

Membrane Structure and Function: Study Notes

Study Guide - Practice Questions