Question 1

Which of the following best describes the primary function of cell signaling in multicellular organisms?

Accepted Answer

To enable cells to communicate and coordinate responses to external signals.

Question 2

A ligand binds to a receptor protein on the cell surface. What is the immediate result of this binding?

Accepted Answer

The receptor undergoes a conformational change.

Question 3

Which of the following is NOT a typical type of signaling molecule?

Accepted Answer

Carbohydrates

Question 4

In the steps of cell signaling, what is the correct order of events?

Accepted Answer

Reception → Transduction → Response

Question 5

Which of the following best describes paracrine signaling?

Accepted Answer

Signals are released and affect only nearby cells in the vicinity.

Question 6

Which type of receptor is most likely to be activated by a hydrophobic signaling molecule such as testosterone?

Accepted Answer

Intracellular receptor

Question 7

Why do only certain cells respond to a specific hormone like testosterone?

Accepted Answer

Only target cells possess the appropriate intracellular receptors for the hormone.

Question 8

Which of the following is a correct example of direct cell signaling?

Accepted Answer

Cells communicating through gap junctions.

Question 9

What is the main role of protein kinases in signal transduction pathways?

Accepted Answer

To add phosphate groups to proteins, often activating them.

Question 10

Which of the following best describes a phosphorylation cascade?

Accepted Answer

A series of proteins that are activated by the addition of phosphate groups.

Question 11

Which type of cell signaling involves the release of neurotransmitters across a synapse?

Accepted Answer

Synaptic signaling

Question 12

Which of the following is a function of phosphatases in cell signaling?

Accepted Answer

They remove phosphate groups from proteins.

Question 13

A mutation in a cell causes its receptor tyrosine kinases to be constantly active. What is a likely consequence?

Accepted Answer

The cell may undergo uncontrolled growth, potentially leading to cancer.

Question 14

Which of the following statements about G-protein-coupled receptors (GPCRs) is correct?

Accepted Answer

They transmit signals by activating G-proteins inside the cell.

Question 15

Which of the following best explains why signal amplification is important in cell signaling?

Accepted Answer

It ensures that a single signaling molecule can produce a large cellular response.

Question 16

Which of the following is true about ligand-gated ion channels?

Accepted Answer

They open in response to the binding of a specific molecule, allowing ions to cross the membrane.

Question 17

Which of the following is a key difference between endocrine and paracrine signaling?

Accepted Answer

Endocrine signaling uses hormones that travel through the bloodstream, while paracrine signaling affects nearby cells.

Question 18

Which of the following best describes the role of second messengers in signal transduction?

Accepted Answer

They relay and amplify signals from receptors to target molecules inside the cell.

Question 19

Which of the following is a correct statement about phosphorylation cascades?

Accepted Answer

They allow for signal amplification and regulation by adding phosphate groups to proteins.

Question 20

A scientist observes that a cell does not respond to a particular hormone. Which is the most likely explanation?

Accepted Answer

The cell lacks the specific receptor for that hormone.

Cell Communication (Ch. 11): Study Notes

Study Guide - Practice Questions