Question 1

Which of the following best describes the process of active transport across a cell membrane?

Accepted Answer

The movement of solutes against their concentration gradient, mediated by carrier proteins and requiring energy expenditure.

Question 2

A proton pump in plant cells uses ATP to transport hydrogen ions ($$H^+) $$out of the cell. What is the primary consequence of this action?

Accepted Answer

It generates a membrane potential by making the inside of the cell more negative relative to the outside.

Question 3

Which equation best represents the relationship between membrane potential ($$V_m$$), ion concentration gradients, and charge distribution?

Accepted Answer

$$V_m = \frac{RT}{F} \ln \left( \frac{[K^+]_{out}}{[K^+]_{in}} \right)$$

Question 4

Which of the following is NOT a function of the plasma membrane in cell signaling?

Accepted Answer

Directly synthesizing hormones for long-distance signaling.

Question 5

A ligand-gated ion channel opens in response to a signaling molecule. What is the immediate effect on the cell?

Accepted Answer

Ions flow through the channel, changing the concentration and charge distribution across the membrane.

Question 6

Which of the following best describes cotransport?

Accepted Answer

The coupling of the downhill diffusion of one substance to the uphill transport of another against its concentration gradient.

Question 7

During receptor-mediated endocytosis, what is the primary role of receptor proteins?

Accepted Answer

To bind specific molecules and trigger vesicle formation for their uptake.

Question 8

Which of the following is a correct sequence for the three stages of cell signaling?

Accepted Answer

Reception → Transduction → Response

Question 9

A hormone binds to its intracellular receptor and activates gene transcription. Which process is most directly involved?

Accepted Answer

Direct activation of transcription factors by the hormone-receptor complex.

Question 10

Which of the following statements about facilitated diffusion is TRUE?

Accepted Answer

It moves solutes down their concentration gradient with the help of transport proteins.

Question 11

Which of the following is a real-world example of bulk transport via exocytosis?

Accepted Answer

Release of insulin from pancreatic cells into the bloodstream.

Question 12

Which statement best explains why the inside of a cell is typically negative relative to the outside?

Accepted Answer

The unequal distribution of anions and cations across the plasma membrane.

Question 13

Which of the following is a function of G protein-coupled receptors (GPCRs) in cell signaling?

Accepted Answer

They activate G proteins upon ligand binding, which then relay signals to other proteins.

Question 14

Which process is illustrated by the equation $$	ext{ATP} ightarrow 	ext{ADP} + 	ext{P}_i in $$the context of membrane transport?

Accepted Answer

ATP hydrolysis supplying energy for active transport

Question 15

Which of the following is an example of local signaling in animal cells?

Accepted Answer

Gap junctions allowing direct cytoplasmic exchange between adjacent cells.

Question 16

Which of the following best describes the role of a ligand in cell signaling?

Accepted Answer

A molecule that specifically binds to a receptor protein, causing a change in shape and activation.

Question 17

Which of the following is a plausible consequence of a malfunctioning electrogenic pump in a neuron?

Accepted Answer

The neuron would be unable to maintain its membrane potential, affecting signal transmission.

Question 18

Which of the following is TRUE about signal transduction pathways?

Accepted Answer

They involve a series of steps linking a stimulus to a specific cellular response.

Question 19

Which of the following is a correct description of phagocytosis?

Accepted Answer

A type of endocytosis in which large particulate substances or small organisms are taken up by the cell.

Membrane Transport and Cell Signaling: Study Notes for General Biology

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