Q: Which equation best represents the relationship between osmolarity, solute concentration, and water movement across a semipermeable membrane?

$Osmolarity = \frac{\text{Number of solute particles}}{\text{Volume of solution}}$

Question 1

Which component of the plasma membrane is primarily responsible for its selective permeability to water-soluble molecules?

Accepted Answer

Phospholipid bilayer

Question 2

A red blood cell is placed in a hypotonic solution. What is the most likely outcome for the cell?

Accepted Answer

It will swell and may burst (lysis) due to water influx.

Question 3

Which type of membrane protein is most likely to function as a channel for ions to pass through the plasma membrane?

Accepted Answer

Integral (transmembrane) protein

Question 4

The sodium-potassium ATPase pump moves ions against their concentration gradients. For each ATP molecule hydrolyzed, how many sodium and potassium ions are moved, and in which direction?

Accepted Answer

3 Na	extsuperscript{+} out, 2 K	extsuperscript{+} in

Question 5

Which equation best represents the relationship between osmolarity, solute concentration, and water movement across a semipermeable membrane?

Accepted Answer

$Osmolarity = \frac{	ext{Number of solute particles}}{	ext{Volume of solution}}$

Question 6

Which of the following best describes the function of desmosomes in epithelial tissue?

Accepted Answer

They anchor cells together to resist mechanical stress.

Question 7

A cell is exposed to a chemical messenger that binds to a receptor protein on its surface. What is the most likely immediate result?

Accepted Answer

The receptor protein changes shape and initiates a series of intracellular changes.

Question 8

Which process allows a cell to engulf large solid particles, such as bacteria, and subsequently digest them?

Accepted Answer

Phagocytosis

Question 9

What is the primary role of the glycocalyx on the cell surface?

Accepted Answer

To facilitate cell recognition and identification

Question 10

Which of the following statements about facilitated diffusion is correct?

Accepted Answer

It uses transport proteins to move substances down their concentration gradient.

Question 11

A neuron has a resting membrane potential of $-70\ 	ext{mV}$. What does this value indicate about the charge distribution across the plasma membrane?

Accepted Answer

The intracellular fluid is more negative than the extracellular fluid.

Question 12

Which type of intercellular junction allows for the direct passage of ions and small molecules between adjacent cells?

Accepted Answer

Gap junctions

Question 13

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

Accepted Answer

It consists of a phospholipid bilayer with proteins and other molecules that can move laterally.

Question 14

Which equation correctly represents the net movement of water during osmosis?

Accepted Answer

$	ext{Net water movement} = 	ext{Water moves from low solute concentration to high solute concentration}$

Question 15

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

Accepted Answer

Storing genetic information

Question 16

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

Accepted Answer

It will shrink due to water loss.

Question 17

Which process is responsible for the secretion of neurotransmitters from a neuron into the synaptic cleft?

Accepted Answer

Exocytosis

Question 18

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

Accepted Answer

It increases membrane stability by stiffening the membrane.

Question 19

Which type of active transport uses the energy stored in ion gradients created by primary active transport to move other substances?

Accepted Answer

Secondary active transport

Question 20

Which of the following is a correct statement about the movement of potassium ions ($K^+$) across the plasma membrane at rest?

Accepted Answer

$K^+$ ions move out of the cell through leak channels, contributing to a negative charge inside the cell.

Cells: Plasma Membranes – Structure, Composition, and Function

Study Guide - Practice Questions

Study Guide - Flashcards