$$ \mathrm{H_2O} $$ moves from $$ [\text{low solute}] to$$ $$ [\text{high solute}] $$

Question 1

Which of the following best describes the 'fluid mosaic model' of the plasma membrane?

Accepted Answer

A dynamic structure with proteins and lipids that can move laterally within the 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 to balance solute concentrations.

Question 4

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

Accepted Answer

Cholesterol helps maintain membrane fluidity by preventing tight packing of phospholipids at low temperatures.

Question 5

Which process requires energy input from the cell?

Accepted Answer

Active transport

Question 6

A cell uses a sodium-potassium pump to move ions across its membrane. Which equation best represents the energy requirement for this process?

Accepted Answer

$$ \mathrm{ATP} \rightarrow \mathrm{ADP} + \mathrm{P_i} $$

Question 7

Which of the following best explains why unsaturated fatty acids increase membrane fluidity?

Accepted Answer

Their kinks prevent tight packing of phospholipids.

Question 8

Which type of membrane protein is most likely to function as a receptor for signal transduction?

Accepted Answer

Integral (transmembrane) protein

Question 9

A plant cell is placed in a hypotonic solution. What is the most likely outcome?

Accepted Answer

The cell will become turgid as water enters, but the cell wall prevents bursting.

Question 10

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

Accepted Answer

Serving as cell identification tags for cell-cell recognition

Question 11

Which of the following best describes facilitated diffusion?

Accepted Answer

Passive movement of molecules through a membrane protein from high to low concentration.

Question 12

Which equation best represents osmosis across a selectively permeable membrane?

Accepted Answer

$$ \mathrm{H_2O} $$ moves from $$ [	ext{low solute}]  to$$ $$ [	ext{high solute}] $$

Question 13

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

Accepted Answer

Synthesis of DNA

Question 14

A cell needs to import glucose against its concentration gradient. Which process will it most likely use?

Accepted Answer

Active transport

Question 15

Which of the following scenarios best illustrates cotransport?

Accepted Answer

A glucose molecule is transported into the cell along with a sodium ion, using the sodium gradient established by active transport.

Question 16

Which of the following best explains why cell membranes are described as 'asymmetrical'?

Accepted Answer

Carbohydrate chains are only found on the extracellular side.

Question 17

Which of the following is an example of bulk transport across the plasma membrane?

Accepted Answer

Exocytosis of neurotransmitters

Question 18

Which of the following factors would NOT increase the rate of diffusion across a membrane?

Accepted Answer

Decreasing the concentration gradient

Question 19

Which of the following best describes the role of the sodium-potassium pump in animal cells?

Accepted Answer

It maintains membrane potential by pumping sodium out and potassium in, using ATP.

Question 20

Which of the following is a real-world example of cell-cell recognition mediated by membrane carbohydrates?

Accepted Answer

ABO blood group compatibility in blood transfusions

Membrane Structure and Transport: Study Notes for General Biology

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