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, cholesterol, and carbohydrates dispersed throughout.

Question 2

What is the primary function of tight junctions in epithelial tissue, such as the lining of the digestive tract?

Accepted Answer

To prevent the passage of molecules between adjacent cells.

Question 3

Which of the following molecules can cross the plasma membrane by simple diffusion?

Accepted Answer

O$$_2$$

Question 4

A red blood cell is placed in a solution containing 2M sucrose. What will happen to the cell?

Accepted Answer

It will shrink due to water leaving the cell (crenation).

Question 5

Which of the following best explains why cholesterol is important in the plasma membrane?

Accepted Answer

It reduces general membrane fluidity and stabilizes the structure.

Question 6

Facilitated diffusion of glucose across the plasma membrane is characterized by all of the following EXCEPT:

Accepted Answer

It requires ATP hydrolysis.

Question 7

Which equation correctly represents the osmolarity of a 1 mM solution of CaCl$$_2$$?

Accepted Answer

$$1 	imes 3 = 3$$ mOsm

Question 8

Which of the following is TRUE regarding the Na$$^+/K$^+$$ ATPase pump?

Accepted Answer

It maintains higher K$$^+$$ inside the cell and higher Na$$^+$$ outside the cell.

Question 9

Which of the following best describes osmosis?

Accepted Answer

Unassisted diffusion of water from an area of more water to less water across a semipermeable membrane.

Question 10

A patient with severe dehydration is given an intravenous solution. Which type of solution should be administered to rehydrate the patient safely?

Accepted Answer

Hypotonic solution

Question 11

Which of the following is a function of plasma membrane proteins?

Accepted Answer

Transport of molecules across the membrane

Question 12

Which type of membrane junction allows the passage of cytoplasmic molecules between adjacent cells, especially in electrically excitable tissues?

Accepted Answer

Gap junctions

Question 13

Which process involves the movement of large particles into a cell by enclosing them in a vesicle that pinches off from the plasma membrane?

Accepted Answer

Endocytosis

Question 14

Which of the following statements about secondary active transport is correct?

Accepted Answer

It relies on the gradient established by primary active transport.

Question 15

A solution containing 0.9% NaCl is considered isotonic to human cells. What does this mean?

Accepted Answer

It has the same osmolarity as the cytoplasm, so cells retain their normal shape.

Question 16

Which of the following is NOT a factor that influences the rate of diffusion across the plasma membrane?

Accepted Answer

Number of mitochondria in the cell

Question 17

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

Accepted Answer

They allow rapid, passive movement of water across the membrane.

Question 18

Which of the following is an example of a symport system in membrane transport?

Accepted Answer

Na$$^+$$ and glucose cotransporter

Question 19

Which of the following statements about vesicular transport is TRUE?

Accepted Answer

Endocytosis requires ATP for vesicle movement.

Question 20

Which of the following best explains why molecules that are ionically bonded have greater osmotic power than those that are covalently bonded?

Accepted Answer

Ionic compounds dissociate into more particles in solution, increasing osmolarity.

Membrane Transport & Excitable Cells – Part 1: Structure and Function of the Plasma Membrane

Study Guide - Practice Questions