Question 1

Which of the following best describes the role of cholesterol in animal cell plasma membranes?

Accepted Answer

It influences membrane fluidity by preventing tight packing of phospholipids.

Question 2

A red blood cell is placed in a solution with a higher concentration of solute than its cytoplasm. What will happen to the cell, and which term best describes the solution?

Accepted Answer

The cell will shrink; the solution is hypertonic.

Question 3

Which type of membrane protein is most likely to be involved in cell recognition and adhesion between multicellular organisms?

Accepted Answer

Integral proteins

Question 4

According to the Fluid Mosaic Model, which statement is correct regarding the plasma membrane?

Accepted Answer

Phospholipids and proteins can move laterally within the membrane.

Question 5

Which equation correctly represents the net movement of molecules during diffusion?

Accepted Answer

$$J = -D \frac{dC}{dx}$$

Question 6

A patient receives an intravenous solution that is isotonic to their blood plasma. What is the expected effect on their red blood cells?

Accepted Answer

Cells will remain unchanged in size.

Question 7

Which of the following best explains why oxygen and carbon dioxide can cross the plasma membrane by simple diffusion?

Accepted Answer

They are nonpolar and small, allowing them to pass through the lipid bilayer.

Question 8

Which structure provides the tightest connection between adjacent cells, restricting movement of proteins and molecules between cells?

Accepted Answer

Tight junctions

Question 9

A cell is placed in a hypotonic solution. Which direction will water move, and what is the likely outcome for the cell?

Accepted Answer

Water will move into the cell; the cell may swell and burst.

Question 10

Which of the following is true about facilitated diffusion?

Accepted Answer

It uses channel or carrier proteins to move substances down their concentration gradient.

Question 11

Which equation best describes the relationship between osmotic pressure ($$\Pi$$), solute concentration ($$C$$), and temperature ($$T) in a $$solution?

Accepted Answer

$$\Pi = iCRT$$

Question 12

Which type of junction allows for the direct passage of ions and small molecules between adjacent animal cells?

Accepted Answer

Gap junctions

Question 13

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

Accepted Answer

They form a bilayer with hydrophilic heads facing outward and hydrophobic tails facing inward.

Question 14

A cell is exposed to a toxin that blocks all carrier proteins in its plasma membrane. Which process would be most directly affected?

Accepted Answer

Facilitated diffusion of glucose

Question 15

Which of the following best describes the concentration gradient?

Accepted Answer

The difference in concentration of a substance across a space.

Question 16

Which membrane protein type is most likely to have both hydrophobic and hydrophilic regions, allowing it to span the entire membrane?

Accepted Answer

Integral proteins

Question 17

Which process is described by the movement of water across a selectively permeable membrane from an area of low solute concentration to high solute concentration?

Accepted Answer

Osmosis

Question 18

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

Accepted Answer

Forming the phospholipid bilayer

Question 19

A scientist observes that a certain molecule can only enter a cell when a specific protein is present in the membrane. Which transport mechanism is most likely involved?

Accepted Answer

Facilitated diffusion

Question 20

Which of the following best describes equilibrium in the context of membrane transport?

Accepted Answer

The state at which the concentration of molecules is the same throughout the solution.

Membrane Transport and Cell Signaling: Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard