Q: Which equation best represents the movement of water during osmosis?

$$\text{Water moves from an area of low solute concentration to high solute concentration across a selectively permeable membrane}$$

Question 1

Which of the following best describes the structure of a biological membrane according to the fluid mosaic model?

Accepted Answer

A double layer of phospholipids with proteins embedded and able to move laterally

Question 2

Which property of phospholipids is most responsible for the formation of the bilayer in cell membranes?

Accepted Answer

Their amphipathic nature, having both hydrophilic heads and hydrophobic tails

Question 3

A researcher observes that a certain membrane remains fluid at lower temperatures than another. Which of the following best explains this observation?

Accepted Answer

The membrane contains a higher proportion of unsaturated fatty acids

Question 4

Which of the following statements about cholesterol in animal cell membranes is correct?

Accepted Answer

Cholesterol reduces membrane fluidity at moderate temperatures but prevents solidification at low temperatures

Question 5

Which of the following molecules would most easily pass through a pure phospholipid bilayer without the aid of a transport protein?

Accepted Answer

Oxygen (O$$_2)$$

Question 6

A cell is placed in a solution and water moves out of the cell, causing it to shrink. Which term best describes the solution?

Accepted Answer

Hypertonic

Question 7

Which of the following best explains why plant cells do not burst when placed in a hypotonic solution?

Accepted Answer

Their cell wall exerts turgor pressure that opposes further water uptake

Question 8

Which of the following is a function of membrane proteins?

Accepted Answer

Signal transduction

Question 9

A person with a genetic mutation that prevents the production of the CCR5 protein is resistant to certain strains of HIV. What is the most direct reason for this resistance?

Accepted Answer

HIV cannot enter the cell without the CCR5 co-receptor

Question 10

Which of the following best describes facilitated diffusion?

Accepted Answer

Movement of a substance down its concentration gradient with the help of a transport protein and no energy input

Question 11

Which equation best represents the movement of water during osmosis?

Accepted Answer

$$	ext{Water moves from an area of low solute concentration to high solute concentration across a selectively permeable membrane}$$

Question 12

Which of the following is true about active transport?

Accepted Answer

It requires energy, usually from ATP hydrolysis

Question 13

The sodium-potassium pump moves sodium and potassium ions across the plasma membrane. Which of the following statements is correct?

Accepted Answer

It moves 3 Na$$^+$$ ions out of the cell and 2 K$$^+$$ ions into the cell, using ATP

Question 14

Which of the following best describes cotransport in plant cells?

Accepted Answer

The diffusion of H$$^+$$ down its gradient drives the active transport of sucrose into the cell

Question 15

Which process is used by white blood cells to engulf bacteria?

Accepted Answer

Phagocytosis

Question 16

Familial hypercholesterolemia is caused by a defect in which cellular process?

Accepted Answer

Receptor-mediated endocytosis of LDL

Question 17

A plant cell is placed in a hypertonic solution. What will most likely happen?

Accepted Answer

The cell will undergo plasmolysis

Question 18

Which of the following is a real-world example of the importance of membrane transport in medicine?

Accepted Answer

Oral rehydration therapy for diarrhea, which uses Na$$^+$$ and glucose cotransporters to restore sodium levels

Question 19

Which of the following statements about membrane carbohydrates is correct?

Accepted Answer

They function as markers for cell identification

Question 20

Which of the following best explains why the sodium-potassium pump is considered an electrogenic pump?

Accepted Answer

It generates a voltage across the membrane by moving more positive charges out than in

Membrane Structure and Function: Study Guide for General Biology

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