Question 1

Which of the following best describes the primary function of cholesterol in the plasma membrane?

Accepted Answer

It stiffens the membrane and decreases water solubility.

Question 2

A red blood cell is placed in a solution and begins to shrink. Which of the following best explains this observation?

Accepted Answer

The solution is hypertonic, so water leaves the cell.

Question 3

Which type of cell junction is most likely to be found between epithelial cells lining the digestive tract, and what is its primary function?

Accepted Answer

Tight junctions; prevent enzymes and microbes from seeping into the bloodstream

Question 4

Which of the following statements about facilitated diffusion is correct?

Accepted Answer

It uses carrier or channel proteins to move substances down their concentration gradient.

Question 5

A patient is given an intravenous solution with an osmolarity higher than their blood plasma. What is the most likely effect on their red blood cells?

Accepted Answer

Cells will shrink due to water efflux, a process called crenation.

Question 6

Which of the following best explains why water can move across the plasma membrane despite being polar?

Accepted Answer

Water moves through aquaporins, which are water-specific channels.

Question 7

Which of the following is true regarding the sodium-potassium pump?

Accepted Answer

It is an example of primary active transport that requires ATP.

Question 8

A mutation causes a single nucleotide substitution in a gene, resulting in a codon that codes for the same amino acid as the original. What type of mutation is this?

Accepted Answer

Silent mutation

Question 9

Which of the following best describes the resting membrane potential (RMP) of a typical cell?

Accepted Answer

It is established mainly by the movement of K$$^+$$ ions and maintained by active transport.

Question 10

Which of the following best describes the role of the glycocalyx on the plasma membrane?

Accepted Answer

It acts as an identity molecule for cell recognition.

Question 11

A solution has a higher concentration of solute particles than the inside of a cell. Which of the following terms best describes this solution, and what is the expected effect on the cell?

Accepted Answer

Hypertonic; cell shrinks

Question 12

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

Accepted Answer

It is selective due to pore size and the charges of amino acids lining the channel.

Question 13

Which of the following best describes a desmosome?

Accepted Answer

An anchoring junction that binds adjacent cells and reduces tension

Question 14

Which of the following is true regarding osmosis?

Accepted Answer

It is the diffusion of water through a selectively permeable membrane.

Question 15

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

Accepted Answer

They act as enzymes, receptors, and transporters.

Question 16

A cell is placed in a hypotonic solution. Which of the following best describes what happens to the cell?

Accepted Answer

Water enters the cell, causing it to swell and possibly lyse.

Question 17

Which of the following best describes secondary active transport?

Accepted Answer

It uses the energy stored in ionic gradients created by primary active transport.

Question 18

Which of the following mutations would most likely result in a frameshift?

Accepted Answer

A single nucleotide insertion

Question 19

Which of the following best explains why the inside of a resting cell is negative compared to the outside?

Accepted Answer

K$$^+$$ ions diffuse out of the cell more easily than Na$$^+$$ ions can enter.

Question 20

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

Accepted Answer

Synthesis of DNA

Ch. 3: The Cellular Level of Organization – Study Guide

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