Question 1

Which of the following best describes the structure of the plasma membrane according to the fluid mosaic model?

Accepted Answer

A double layer of phospholipids with proteins embedded or attached, allowing lateral movement

Question 2

Which component of the plasma membrane is primarily responsible for its selective permeability?

Accepted Answer

Phospholipid bilayer

Question 3

What is the main effect of cholesterol on the plasma membrane at low temperatures?

Accepted Answer

It hinders the close packing of phospholipids, maintaining fluidity

Question 4

A red blood cell is placed in a solution and begins to swell and burst. What type of solution is it in, and why does this occur?

Accepted Answer

Hypotonic; water moves into the cell due to lower solute concentration outside

Question 5

Which of the following molecules would most easily diffuse through a pure phospholipid bilayer without the aid of a protein?

Accepted Answer

O$$_2$$

Question 6

What is the primary function of integral membrane proteins?

Accepted Answer

To span the membrane and participate in transport, signaling, and other functions

Question 7

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

Accepted Answer

Their kinks prevent close packing of phospholipid tails

Question 8

A plant cell uses a proton pump to create a gradient, then uses a cotransporter to bring sucrose into the cell. What type of transport is this an example of?

Accepted Answer

Cotransport (secondary active transport)

Question 9

Which of the following statements about facilitated diffusion is correct?

Accepted Answer

It uses channel or carrier proteins to move molecules down their concentration gradient

Question 10

What is the main reason that ions such as Na$$^+$$ and Cl$$^-$$ cannot easily cross the plasma membrane?

Accepted Answer

They are hydrophilic and cannot pass through the hydrophobic core of the membrane

Question 11

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

Accepted Answer

Water moves from an area of higher free water concentration to lower free water concentration

Question 12

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

Accepted Answer

Storage of genetic information

Question 13

A cell is placed in a hypertonic solution. What will happen to the cell and why?

Accepted Answer

It will shrink because water leaves the cell

Question 14

Which of the following best explains the negative membrane potential in animal cells?

Accepted Answer

There are more negative ions inside the cell than outside

Question 15

Which process is responsible for the bulk uptake of specific molecules, such as LDL cholesterol, into animal cells?

Accepted Answer

Receptor-mediated endocytosis

Question 16

Which of the following best describes the role of the sodium-potassium pump in animal cells?

Accepted Answer

It uses ATP to move 3 Na$$^+$$ out and 2 K$$^+ in$$, maintaining membrane potential

Question 17

Which of the following statements about glycoproteins in the plasma membrane is correct?

Accepted Answer

They are synthesized and modified in the ER and Golgi apparatus

Question 18

Which of the following is a correct statement about passive transport?

Accepted Answer

It includes diffusion and facilitated diffusion

Question 19

A mutation causes a cell to lack functional aquaporins. Which process would be most directly affected?

Accepted Answer

Facilitated diffusion of water

Question 20

Which of the following best describes the electrochemical gradient?

Accepted Answer

It is the combined effect of a chemical gradient and an electrical gradient on ion movement

Membrane Structure and Function: Study Notes for Biology College Students

Study Guide - Practice Questions

Study Guide - Flashcards