$ \text{H}_2\text{O} \rightarrow \text{from low solute concentration to high solute concentration across a membrane} $

Question 1

Which of the following best explains why phospholipids spontaneously form bilayers in aqueous environments?

Accepted Answer

Their hydrophilic heads interact with water, while their hydrophobic tails avoid water.

Question 2

A patient is given an intravenous solution that is hypertonic relative to their red blood cells. What will happen to the cells?

Accepted Answer

Water will move out of the cells, causing them to shrink.

Question 3

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

Accepted Answer

It requires input of energy in the form of ATP to function.

Question 4

Which of the following best describes the amphipathic nature of phospholipids?

Accepted Answer

They contain both a hydrophilic region and a hydrophobic region.

Question 5

A researcher adds a large, charged molecule to one side of a synthetic phospholipid bilayer. What is the most likely outcome?

Accepted Answer

The molecule will cross slowly, if at all, due to selective permeability.

Question 6

Which of the following is a key difference between fats and phospholipids?

Accepted Answer

Phospholipids contain a hydrophilic head, while fats do not.

Question 7

Which of the following equations best represents the process of osmosis?

Accepted Answer

$ 	ext{H}_2	ext{O} ightarrow 	ext{from low solute concentration to high solute concentration across a membrane} $

Question 8

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

Accepted Answer

Storing genetic information

Question 9

Which of the following best describes the movement of phospholipids within the membrane?

Accepted Answer

They move laterally within one layer but rarely flip to the other side.

Question 10

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

Accepted Answer

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

Question 11

Which of the following is true about facilitated diffusion?

Accepted Answer

It involves transmembrane proteins assisting passive transport.

Question 12

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

Accepted Answer

It is a steroid that helps maintain membrane fluidity.

Question 13

Which of the following is a property of saturated fatty acids?

Accepted Answer

They have only single bonds between carbons.

Question 14

Which of the following best explains why fats store more energy than carbohydrates?

Accepted Answer

Fats have a larger number of high-energy nonpolar bonds in their fatty acid chains.

Question 15

Which of the following is true about the fluid-mosaic model of membrane structure?

Accepted Answer

The membrane is a dynamic mosaic of phospholipids and proteins.

Question 16

Which of the following best describes the function of carrier proteins in the membrane?

Accepted Answer

They selectively pick up and transport specific molecules across the membrane.

Question 17

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

Accepted Answer

Movement of glucose against its gradient powered by the sodium gradient

Question 18

Which of the following best describes the role of amphipathic proteins in the membrane?

Accepted Answer

Their hydrophobic regions anchor them into the lipid bilayer.

Question 19

Which of the following is true about the movement of ions across membranes?

Accepted Answer

Ions require channel proteins to move down their electrochemical gradients.

Question 20

Which of the following best describes the evolutionary significance of protocells?

Accepted Answer

They were simple vesicle-like structures that may have harbored nucleic acids.

Lipids, Membranes, and the First Cells: Study Notes

Study Guide - Practice Questions