Q: Which equation correctly represents osmolarity for a solution containing 1 mM NaCl and 1 mM glucose?

$$\text{Osmolarity} = 3\ \text{mOsmol/L}$$

Question 1

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

Accepted Answer

A dynamic structure with proteins and cholesterol embedded in a phospholipid bilayer, allowing lateral movement.

Question 2

What is the primary function of cholesterol in the plasma membrane?

Accepted Answer

To stabilize the membrane and reduce its fluidity.

Question 3

Which type of membrane junction is most important in preventing the passage of molecules between adjacent cells in the lining of the digestive tract?

Accepted Answer

Tight junctions

Question 4

A red blood cell (RBC) is placed in a solution containing 0.9% NaCl. What will happen to the cell?

Accepted Answer

It will remain unchanged because the solution is isotonic.

Question 5

Which of the following is a characteristic of facilitated diffusion?

Accepted Answer

It is specific, saturable, and moves molecules down their concentration gradient.

Question 6

Which equation correctly represents osmolarity for a solution containing 1 mM NaCl and 1 mM glucose?

Accepted Answer

$$	ext{Osmolarity} = 3\ 	ext{mOsmol/L}$$

Question 7

Which of the following best explains why minor damage to the plasma membrane is usually not a problem for the cell?

Accepted Answer

The fluid nature of the membrane allows phospholipids and proteins to move and self-seal small tears.

Question 8

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

Accepted Answer

Synthesis of ATP

Question 9

A patient is given a hypertonic solution intravenously to treat edema. What is the expected effect on the patient's cells?

Accepted Answer

Cells will shrink as water moves out into the extracellular fluid.

Question 10

Which of the following statements about the Na+/K+ ATPase pump is correct?

Accepted Answer

It uses ATP to move Na+ out of the cell and K+ into the cell against their concentration gradients.

Question 11

Which of the following best describes the process of osmosis?

Accepted Answer

Movement of water from an area of low solute concentration to high solute concentration across a semipermeable membrane.

Question 12

Which of the following is true regarding receptor-mediated endocytosis?

Accepted Answer

It allows the cell to selectively take in specific molecules by enclosing them in vesicles.

Question 13

Which of the following is a difference between symport and antiport transporters?

Accepted Answer

Symporters move two substances in the same direction, while antiporters move them in opposite directions.

Question 14

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

Accepted Answer

Oxygen ($$O_2)$$

Question 15

A cell is placed in a solution containing 300 mOsm NaCl and 60 mOsm urea. The cell membrane is permeable to urea but not to NaCl. What is the initial response of the cell?

Accepted Answer

Urea will enter the cell, and water will follow, causing the cell to swell initially.

Question 16

Which of the following is a property of channel-mediated facilitated diffusion?

Accepted Answer

Channels are selective due to pore size and charge, and movement is always down the concentration gradient.

Question 17

Which of the following best describes filtration as a transport mechanism?

Accepted Answer

Movement of solutes and fluid through a membrane due to hydrostatic pressure.

Question 18

Which of the following is true about the glycocalyx?

Accepted Answer

It is a layer of carbohydrates attached to lipids and proteins on the extracellular face of the plasma membrane.

Question 19

Which of the following is NOT a passive transport mechanism?

Accepted Answer

Primary active transport

Question 20

Which of the following best explains why the Na+/K+ ATPase pump is essential for nerve and muscle cell function?

Accepted Answer

It maintains the concentration gradients of Na+ and K+ necessary for action potentials.

Cell Membrane Structure and Transport Processes

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