$\text{Water moves from a region of lower [solute] to a region of higher [solute]}$

Question 1

Which property of the plasma membrane allows it to regulate the movement of substances into and out of the cell?

Accepted Answer

It is selectively permeable, allowing some substances to cross more easily than others.

Question 2

The fluid mosaic model describes the plasma membrane as:

Accepted Answer

A mosaic of protein molecules bobbing in a fluid bilayer of phospholipids.

Question 3

Which of the following best explains why phospholipids are described as amphipathic?

Accepted Answer

They contain both hydrophobic and hydrophilic regions.

Question 4

What is the main function of membrane proteins that span the entire thickness of the membrane?

Accepted Answer

They serve as transmembrane proteins involved in transport and signaling.

Question 5

Which of the following statements about membrane fluidity is correct?

Accepted Answer

Unsaturated fatty acid tails increase membrane fluidity due to kinks that prevent tight packing.

Question 6

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

Accepted Answer

The cell will gain water and may burst.

Question 7

Which equation best represents the movement of water during osmosis?

Accepted Answer

$	ext{Water moves from a region of lower [solute] to a region of higher [solute]}$

Question 8

Which type of transport requires energy input from the cell?

Accepted Answer

Active transport

Question 9

The sodium-potassium pump is an example of:

Accepted Answer

Active transport that exchanges Na$^+$ for K$^+$ across the plasma membrane.

Question 10

Which of the following best describes the role of cholesterol in animal cell membranes at moderate temperatures?

Accepted Answer

It reduces membrane fluidity by restraining phospholipid movement.

Question 11

Which of the following molecules can most easily cross the plasma membrane without assistance?

Accepted Answer

Hydrophobic (nonpolar) molecules such as O$_2$ and CO$_2$.

Question 12

What is the main difference between channel proteins and carrier proteins in facilitated diffusion?

Accepted Answer

Channel proteins form tunnels for specific molecules, while carrier proteins change shape to move molecules across.

Question 13

Which process allows cells to take in large molecules or particles by forming new vesicles from the plasma membrane?

Accepted Answer

Endocytosis

Question 14

During synaptic signaling in animal nervous systems, which molecule is released from the nerve cell to transmit the signal?

Accepted Answer

Neurotransmitter

Question 15

Which of the following is a correct sequence for cell signaling?

Accepted Answer

Reception → Transduction → Response

Question 16

A plant cell placed in a hypertonic solution will most likely:

Accepted Answer

Lose water and undergo plasmolysis.

Question 17

Which type of cell signaling involves hormones traveling through the bloodstream to reach target cells?

Accepted Answer

Endocrine (hormonal) signaling

Question 18

Which equation best describes the movement of solute during passive diffusion?

Accepted Answer

$	ext{Solute moves from an area of high concentration to an area of low concentration}$

Question 19

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

Accepted Answer

Synthesis of DNA

Question 20

Which process is responsible for amplifying a signal inside a cell after reception?

Accepted Answer

Signal transduction pathway involving cascades of molecular interactions

Membrane Transport & Cell Signaling: Structure, Function, and Mechanisms

Study Guide - Practice Questions