Q: Which equation correctly represents the calculation of membrane potential ($$V_m) $$based on the Nernst equation for a single ion?

$$V_m = \frac{RT}{zF} \ln \frac{[\text{ion}]_{\text{outside}}}{[\text{ion}]_{\text{inside}}}$$

Question 1

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

Accepted Answer

Their amphipathic nature causes hydrophobic tails to cluster together, while hydrophilic heads face outward toward water.

Question 2

A cell membrane is described as a 'fluid mosaic.' Which component is primarily responsible for regulating membrane fluidity at different temperatures?

Accepted Answer

Cholesterol

Question 3

Which of the following statements about membrane carbohydrates is correct?

Accepted Answer

They are located on the exterior side and are bound to proteins or lipids, forming glycoproteins and glycolipids.

Question 4

A red blood cell is placed in a solution with a higher solute concentration than its cytoplasm. What will happen to the cell, and what is the term for this type of solution?

Accepted Answer

The cell will shrink; the solution is hypertonic.

Question 5

Which equation correctly represents the calculation of membrane potential ($$V_m) $$based on the Nernst equation for a single ion?

Accepted Answer

$$V_m = \frac{RT}{zF} \ln \frac{[	ext{ion}]_{	ext{outside}}}{[	ext{ion}]_{	ext{inside}}}$$

Question 6

Facilitated diffusion differs from simple diffusion in that:

Accepted Answer

Facilitated diffusion uses transport proteins to move molecules down their concentration gradient without energy input.

Question 7

Which type of membrane transport is responsible for the uptake of large particles, such as bacteria, by immune cells?

Accepted Answer

Phagocytosis

Question 8

A plant cell is placed in pure water. Which process will occur, and what is the direction of water movement?

Accepted Answer

Osmosis; water moves into the cell.

Question 9

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

Accepted Answer

They are integral membrane proteins that can span the membrane and attach the cell to the extracellular matrix.

Question 10

Which of the following is a correct statement about the sodium-potassium pump?

Accepted Answer

It requires ATP to move sodium out of the cell and potassium into the cell, maintaining membrane potential.

Question 11

Which of the following is an example of a second messenger in cell signaling?

Accepted Answer

Cyclic AMP ($$cAMP)$$

Question 12

A cell uses receptor-mediated endocytosis to import cholesterol. What triggers the formation of vesicles in this process?

Accepted Answer

Binding of a ligand to specific receptor sites on the cell membrane.

Question 13

Which of the following best describes the difference between uniporters, symporters, and antiporters?

Accepted Answer

Uniporters carry one molecule; symporters carry two molecules in the same direction; antiporters carry two molecules in opposite directions.

Question 14

Which process is responsible for the release of neurotransmitters from a neuron into the synaptic cleft?

Accepted Answer

Exocytosis

Question 15

Which of the following is true regarding the effect of cholesterol on membrane fluidity at low temperatures?

Accepted Answer

Cholesterol increases membrane fluidity by preventing tight packing of phospholipids.

Question 16

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

Accepted Answer

Storage of genetic information

Question 17

Which stage of cell signaling involves the conversion of a signal to a cellular response via a signal transduction pathway?

Accepted Answer

Transduction

Question 18

Which type of cell signaling involves hormones traveling through the bloodstream to reach target cells?

Accepted Answer

Endocrine signaling

Question 19

Which enzyme is responsible for adding a phosphate group to a protein during phosphorylation?

Accepted Answer

Kinase

Question 20

A freshwater protist, Paramecium caudatum, lives in a hypotonic environment. What adaptation allows it to survive?

Accepted Answer

It uses a contractile vacuole to pump excess water out of the cell.

Membrane Structure, Transport, and Cell Signaling

Guida di studio - Domande di pratica

Study guide - Flashcard