Question 1

Which of the following best describes the function of the plasma membrane in a eukaryotic cell?

Accepted Answer

It isolates the cell from its environment and regulates exchange of substances.

Question 2

According to the fluid mosaic model, which statement is correct about the structure of biological membranes?

Accepted Answer

Proteins are embedded within a fluid phospholipid bilayer and can move laterally.

Question 3

A red blood cell is placed in a hypertonic solution. What will most likely happen to the cell?

Accepted Answer

It will shrink as water moves out of the cell.

Question 4

Which process requires energy input from ATP to move molecules across a membrane against their concentration gradient?

Accepted Answer

Active transport

Question 5

Which of the following is an example of passive transport across a biological membrane?

Accepted Answer

Movement of glucose into a cell via a carrier protein down its concentration gradient

Question 6

A cell is placed in an isotonic solution. What is the net movement of water across the plasma membrane?

Accepted Answer

There is no net movement of water.

Question 7

Which of the following best describes facilitated diffusion?

Accepted Answer

Movement of molecules down their concentration gradient with the help of a protein.

Question 8

Which of the following statements about osmosis is correct?

Accepted Answer

Osmosis is the diffusion of water from a region of low solute concentration to high solute concentration.

Question 9

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

Accepted Answer

Synthesis of DNA

Question 10

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

Accepted Answer

The cell will gain water, swell, and become turgid.

Question 11

Which of the following best explains why the plasma membrane is described as 'selectively permeable'?

Accepted Answer

It allows some substances to cross more easily than others.

Question 12

Which of the following scenarios is an example of exocytosis?

Accepted Answer

A neuron releasing neurotransmitters into a synaptic cleft

Question 13

Which of the following statements about the laws of thermodynamics is correct?

Accepted Answer

The second law states that every energy transfer increases the disorder (entropy) of the universe.

Question 14

Which of the following reactions is exergonic?

Accepted Answer

Breakdown of ATP to ADP and inorganic phosphate

Question 15

A cell is actively transporting sodium ions out of the cell and potassium ions into the cell. Which equation best represents the energy requirement for this process?

Accepted Answer

$$ \Delta G \u003e 0 $$

Question 16

Which of the following best describes the difference between simple diffusion and facilitated diffusion?

Accepted Answer

Facilitated diffusion requires a protein to help move molecules across the membrane.

Question 17

Which of the following is true about the movement of water during osmosis?

Accepted Answer

Water moves from an area of low solute concentration to high solute concentration.

Question 18

Which of the following is a real-life example of receptor-mediated endocytosis?

Accepted Answer

A liver cell taking up LDL cholesterol from the blood

Question 19

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

Accepted Answer

They serve as recognition sites for cell-to-cell communication.

Question 20

A scientist observes that a certain molecule can cross the plasma membrane only when a specific protein is present, and the process does not require ATP. Which transport mechanism is most likely involved?

Accepted Answer

Facilitated diffusion

Cell Membrane Structure, Function, and Energy Flow in Cells

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