Question 1

Which of the following best describes the difference between osmolarity and tonicity?

Accepted Answer

Osmolarity refers to the concentration of solute particles per liter of solution, while tonicity describes the effect of a solution on the volume of a cell.

Question 2

A red blood cell is placed in a solution and swells until it bursts. Which of the following best describes the solution?

Accepted Answer

The solution is hypotonic relative to the cell cytoplasm.

Question 3

Which equation correctly converts molarity ($M$) to osmolarity ($Osm$) for a solution of sodium chloride ($NaCl$)?

Accepted Answer

$Osm = M 	imes 2$

Question 4

Which of the following is a property of simple diffusion across a cell membrane?

Accepted Answer

It does not require energy and moves molecules down their concentration gradient.

Question 5

A cell membrane is more permeable to potassium ions ($K^+$) than sodium ions ($Na^+$). What is the main consequence of this difference?

Accepted Answer

The resting membrane potential is closer to the equilibrium potential of $K^+$.

Question 6

Which of the following best describes the mechanism of the Na$^+$/K$^+$-ATPase pump?

Accepted Answer

It uses ATP to move 3 Na$^+$ ions out of the cell and 2 K$^+$ ions into the cell against their concentration gradients.

Question 7

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

Accepted Answer

The Na$^+$/glucose symporter uses the Na$^+$ gradient to transport glucose into the cell.

Question 8

Which of the following best explains why a solution can be isosmotic but hypotonic?

Accepted Answer

The solution contains penetrating solutes that enter the cell, causing water to follow and the cell to swell.

Question 9

Which of the following is NOT a property of diffusion?

Accepted Answer

Diffusion requires direct input of cellular energy (ATP).

Question 10

A patient is given an intravenous solution of 0.9% NaCl. What is the tonicity of this solution relative to red blood cells?

Accepted Answer

Isotonic

Question 11

Which of the following best describes facilitated diffusion?

Accepted Answer

It uses membrane proteins to transport molecules down their concentration gradient without energy input.

Question 12

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

Accepted Answer

They bind specific ligands and initiate cellular responses.

Question 13

Which of the following best describes the process of exocytosis?

Accepted Answer

Vesicles fuse with the plasma membrane to release their contents outside the cell.

Question 14

Which of the following is a key difference between channel proteins and carrier proteins?

Accepted Answer

Channel proteins form continuous pores, while carrier proteins undergo conformational changes to transport molecules.

Question 15

Which of the following best describes the role of clathrin in receptor-mediated endocytosis?

Accepted Answer

Clathrin helps form coated pits that facilitate vesicle formation during endocytosis.

Question 16

Which of the following best explains why the Na$^+$/K$^+$-ATPase is considered a primary active transporter?

Accepted Answer

It directly uses the energy from ATP hydrolysis to move ions against their gradients.

Question 17

Which of the following is an example of a nonpenetrating solute in human physiology?

Accepted Answer

Na$^+$ (sodium ion)

Question 18

Which of the following best describes the process of transcytosis?

Accepted Answer

A molecule is transported across a cell by endocytosis on one side and exocytosis on the other.

Question 19

Which of the following is a property of facilitated diffusion but NOT simple diffusion?

Accepted Answer

It exhibits saturation when all transporters are occupied.

Membrane Transport, Osmosis, and Resting Membrane Potential: Study Notes for Anatomy & Physiology

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