Question 1

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

Accepted Answer

A phospholipid bilayer with proteins embedded within and moving laterally

Question 2

Which property of phospholipids is primarily responsible for the formation of the bilayer structure in biological membranes?

Accepted Answer

Their amphipathic nature, having both hydrophilic heads and hydrophobic tails

Question 3

A red blood cell is placed in a solution and begins to swell and eventually bursts. Which term best describes the solution relative to the cell's cytoplasm?

Accepted Answer

Hypotonic

Question 4

Which of the following statements about membrane proteins is correct?

Accepted Answer

Transmembrane proteins are a type of integral protein that extend completely through the membrane

Question 5

Which process requires energy input from the cell and moves substances against their concentration gradient?

Accepted Answer

Active transport

Question 6

The sodium-potassium pump is an example of which type of membrane transport?

Accepted Answer

Primary active transport

Question 7

Which of the following best explains why cholesterol is important in animal cell membranes?

Accepted Answer

It acts as a fluidity buffer, maintaining membrane stability at different temperatures

Question 8

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

Accepted Answer

The cell will lose water, and the plasma membrane will pull away from the cell wall (plasmolysis)

Question 9

Which of the following is true about facilitated diffusion?

Accepted Answer

It uses transport proteins to move molecules down their concentration gradient

Question 10

Which scenario best illustrates secondary active transport (cotransport)?

Accepted Answer

A glucose molecule is transported into a cell along with a sodium ion, where sodium moves down its gradient and glucose moves against its gradient

Question 11

Which of the following best describes osmosis?

Accepted Answer

The movement of water molecules from low to high solute concentration across a selectively permeable membrane

Question 12

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

Accepted Answer

Providing a rigid structure to the membrane

Question 13

A white blood cell engulfs a bacterium by surrounding it with its plasma membrane and forming a vesicle. This process is called:

Accepted Answer

Phagocytosis

Question 14

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

Accepted Answer

It allows some substances to pass while blocking others

Question 15

Which of the following is a correct sequence of events in cell signaling?

Accepted Answer

Reception → Transduction → Response

Question 16

Which of the following best describes the role of phosphorylation in signal transduction pathways?

Accepted Answer

It adds a phosphate group to a protein, often activating it

Question 17

A cell is exposed to a hormone that cannot cross the plasma membrane. Where would you expect to find the receptor for this hormone?

Accepted Answer

On the cell membrane surface

Question 18

Which of the following is an example of a local signaling mechanism?

Accepted Answer

Paracrine signaling between neighboring cells

Question 19

Which equation best represents the net movement of water during osmosis across a selectively permeable membrane?

Accepted Answer

$$ 	ext{Water moves from} \; 	ext{high} \; \Psi_w \; 	ext{to low} \; \Psi_w $$

Question 20

A patient is given an intravenous solution that is hypertonic relative to their blood plasma. What is the most likely effect on their red blood cells?

Accepted Answer

The cells will shrink as water leaves them

Biological Membranes: Structure, Function, and Transport Mechanisms

Guida di studio - Domande di pratica

Study guide - Flashcard