Question 1

Which of the following best explains why the plasma membrane is described as a 'fluid mosaic model'?

Accepted Answer

The membrane is a fluid structure with various proteins embedded, allowing lateral movement of both lipids and proteins.

Question 2

Which of the following molecules can cross the phospholipid bilayer most easily without the help of a transport protein?

Accepted Answer

O$$_2$$

Question 3

A bacterial cell is placed in a hypertonic solution. What is the most likely outcome for the cell?

Accepted Answer

The cell will lose water and shrink as water moves out.

Question 4

Which of the following statements about the role of cholesterol in eukaryotic plasma membranes is correct?

Accepted Answer

Cholesterol helps maintain membrane fluidity by preventing tight packing of phospholipids.

Question 5

Which of the following best describes the function of a carrier protein in facilitated diffusion?

Accepted Answer

It binds to a specific molecule, changes conformation, and transports the molecule down its concentration gradient.

Question 6

A patient is given an intravenous solution of pure water instead of saline. What is the most likely effect on their red blood cells?

Accepted Answer

The cells will swell and may burst due to water entering the cells.

Question 7

Which of the following is a function of membrane glycoproteins?

Accepted Answer

They serve as identification tags for cell-cell recognition.

Question 8

Which of the following best explains why prokaryotic cells can generate ATP at their plasma membrane?

Accepted Answer

Prokaryotes use the plasma membrane for ATP synthesis because they lack membrane-bound organelles.

Question 9

Which of the following is true regarding the movement of water during osmosis?

Accepted Answer

Water moves from a region of low solute concentration to high solute concentration.

Question 10

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

Accepted Answer

The cell will become turgid as water enters, which is the normal state for plant cells.

Question 11

Which of the following is a distinguishing feature of the plasma membrane in Mycoplasma compared to most other prokaryotes?

Accepted Answer

It contains sterols and cholesterols to maintain membrane fluidity.

Question 12

Which of the following best describes the function of the Na$$ ^+ /K$ ^+ $$ pump in neurons?

Accepted Answer

It uses ATP to move Na$$ ^+ $$ out of the cell and K$$ ^+ $$ into the cell, maintaining the membrane potential.

Question 13

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

Accepted Answer

DNA replication

Question 14

Which of the following scenarios best illustrates the concept of selective permeability of the plasma membrane?

Accepted Answer

O$$_2$$ can diffuse freely, but Na$$ ^+ $$ requires a channel protein to cross the membrane.

Question 15

Which of the following best describes the difference between simple diffusion and facilitated diffusion?

Accepted Answer

Facilitated diffusion requires a transport protein, while simple diffusion does not.

Question 16

A cell is observed to have a large number of aquaporins in its plasma membrane. What is the most likely function of these proteins?

Accepted Answer

Facilitating the rapid movement of water across the membrane

Question 17

Which of the following best explains why plant cells do not burst when placed in a hypotonic solution?

Accepted Answer

Plant cells have a rigid cell wall that prevents excessive expansion.

Question 18

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

Accepted Answer

Uptake of low-density lipoproteins (LDL) by cells

Question 19

Which of the following best describes the role of the glycocalyx in prokaryotic and eukaryotic cells?

Accepted Answer

It provides a dynamic barrier for communication, protection, and adherence.

Functional Anatomy of Prokaryotic and Eukaryotic Cells: Plasma Membrane and Transport

Study Guide - Practice Questions