$$\text{Water moves from low solute concentration to high solute concentration}$$

Question 1

Which of the following best explains why phospholipids spontaneously form bilayers in aqueous environments?

Accepted Answer

Their hydrophilic heads interact with water, while hydrophobic tails avoid it.

Question 2

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

Accepted Answer

The cell will shrink because water moves out of the cell.

Question 3

Which type of membrane protein is most likely to be involved in cell-cell recognition?

Accepted Answer

Integral proteins with attached glycoprotein chains

Question 4

Which of the following statements about membrane fluidity is correct?

Accepted Answer

Unsaturated fatty acids increase membrane fluidity.

Question 5

A patient’s cells lack functional CCR5 receptors. What is the medical significance of this?

Accepted Answer

Their cells are resistant to HIV infection.

Question 6

Which equation best represents the movement of water during osmosis?

Accepted Answer

$$	ext{Water moves from low solute concentration to high solute concentration}$$

Question 7

Which of the following molecules can diffuse most easily across the plasma membrane without a transport protein?

Accepted Answer

O$$_2$$

Question 8

The sodium-potassium pump is an example of:

Accepted Answer

Active transport

Question 9

Which process requires energy input from ATP to move substances against their concentration gradient?

Accepted Answer

Active transport

Question 10

A cell uses receptor-mediated endocytosis to import cholesterol. Which step is unique to this process compared to phagocytosis and pinocytosis?

Accepted Answer

Specific uptake via membrane receptors

Question 11

Which of the following best describes the sidedness of biological membranes?

Accepted Answer

Membranes are asymmetrical, with distinct inside and outside faces.

Question 12

Which of the following is a function of glycoproteins in the plasma membrane?

Accepted Answer

Cell recognition

Question 13

Which of the following best explains why facilitated diffusion is necessary for glucose transport across the plasma membrane?

Accepted Answer

Glucose is a large, hydrophilic molecule that cannot cross the lipid bilayer unaided.

Question 14

Which of the following equations represents the electrochemical gradient across a membrane?

Accepted Answer

$$\Delta G = RT \ln \left( \frac{[C]_{in}}{[C]_{out}} \right) + zF\Delta V$$

Question 15

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

Accepted Answer

Synthesis of phospholipids

Question 16

A plant cell is placed in an isotonic solution. What will happen to the cell?

Accepted Answer

There will be no net movement of water.

Question 17

Which of the following statements about cholesterol in the plasma membrane is correct?

Accepted Answer

Cholesterol increases membrane fluidity at low temperatures and decreases it at high temperatures.

Question 18

Which process is responsible for the export of large molecules from the cell?

Accepted Answer

Exocytosis

Question 19

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

Accepted Answer

They facilitate the passive movement of water across the membrane.

Question 20

A cell uses a co-transport mechanism to import sucrose along with H$$^+. $$Which of the following best describes this process?

Accepted Answer

The import of sucrose is coupled to the movement of H$$^+$$ down its gradient.

Membrane Structure and Function: Study Notes

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