Q: Which equation best represents the rate of diffusion according to Fick's Law?

$$Rate = D \times A \times \frac{\Delta C}{d}$$

Question 1

Which of the following best describes the Fluid Mosaic Model of the plasma membrane?

Accepted Answer

A dynamic structure with proteins and carbohydrates embedded in a flexible phospholipid bilayer.

Question 2

Which component of the plasma membrane is primarily responsible for its selective permeability?

Accepted Answer

Phospholipid bilayer

Question 3

A red blood cell is placed in a hypertonic solution. What will happen to the cell, and why?

Accepted Answer

It will shrink because water leaves the cell by osmosis.

Question 4

Which of the following is a function of membrane proteins?

Accepted Answer

Acting as hormone binding sites

Question 5

What is the main difference between passive diffusion and facilitated diffusion?

Accepted Answer

Facilitated diffusion uses membrane proteins to transport molecules that cannot pass through the lipid bilayer.

Question 6

Which equation best represents the rate of diffusion according to Fick's Law?

Accepted Answer

$$Rate = D 	imes A 	imes \frac{\Delta C}{d}$$

Question 7

Cholesterol in the plasma membrane serves which primary function?

Accepted Answer

Stabilizing the membrane and regulating its fluidity depending on temperature

Question 8

A cell uses the sodium-potassium pump to maintain ion gradients. Which statement correctly describes this process?

Accepted Answer

It uses ATP to move sodium out of the cell and potassium into the cell against their concentration gradients.

Question 9

Which of the following molecules can most easily cross the phospholipid bilayer by simple diffusion?

Accepted Answer

Oxygen ($$O_2)$$

Question 10

What is the primary role of aquaporins in the plasma membrane?

Accepted Answer

Allowing rapid movement of water molecules across the membrane

Question 11

Which process describes the import of macromolecules into the cell by the plasma membrane pinching inward to form a vesicle?

Accepted Answer

Endocytosis

Question 12

A cell is placed in a solution with a lower solute concentration than its cytoplasm. What type of solution is this, and what will happen to the cell?

Accepted Answer

Hypotonic; the cell will swell.

Question 13

Which of the following best explains why polar molecules require carrier proteins to cross the plasma membrane?

Accepted Answer

The hydrophobic core of the phospholipid bilayer prevents polar molecules from diffusing through.

Question 14

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

Accepted Answer

Synthesizing phospholipids

Question 15

During receptor-mediated endocytosis, what is the role of clathrin?

Accepted Answer

It stabilizes the vesicle and helps carry the molecule into the cytoplasm.

Question 16

Which of the following statements about osmosis is correct?

Accepted Answer

Osmosis is the passive movement of water molecules across a partially permeable membrane.

Question 17

Which process is responsible for the export of macromolecules from the cell?

Accepted Answer

Exocytosis

Question 18

A cell is actively transporting $$Na^+$$ ions out and $$K^+$$ ions in. If the cell uses 1 ATP molecule for every 3 $$Na^+$$ exported and 2 $$K^+$$ imported, what is the ratio of $$Na^+ to$$ $$K^+$$ transported per ATP?

Accepted Answer

$$3:2$$

Question 19

Which of the following would increase the fluidity of a cell membrane?

Accepted Answer

Increasing the proportion of unsaturated fatty acids in phospholipids

Question 20

Which statement best describes the movement of water in plant cells with a rigid cell wall when placed in a hypotonic solution?

Accepted Answer

Water enters the cell, but the cell wall prevents excessive swelling.

Cell Membrane Structure and Transport Mechanisms (Chapter 5 Study Notes)

Study Guide - Practice Questions

Study Guide - Flashcards