Question 1

Which of the following is an example of paracrine communication in cell signaling?

Accepted Answer

Growth factors released by one cell binding to receptors on a neighboring cell, leading to a change in activity.

Question 2

Which statement best describes the difference between lipophilic and lipophobic ligands?

Accepted Answer

Lipophilic ligands cross the plasma membrane to bind to intracellular receptors, often leading to slow responses by altering gene expression.

Question 3

Which of the following is FALSE about membrane receptors?

Accepted Answer

Ion channel receptors elicit a much slower response than G-protein coupled receptors.

Question 4

A patient is given a drug that acts as an antagonist to a specific receptor. What is the expected effect?

Accepted Answer

The drug will bind to the receptor and block the natural ligand from activating it.

Question 5

Which equation best represents the concept of receptor saturation?

Accepted Answer

$R_{total} = R_{free} + R_{bound}$

Question 6

Which of the following mechanisms could explain why a medication becomes less effective after prolonged use?

Accepted Answer

The receptors that the drug binds to have been downregulated.

Question 7

In the GPCR-adenylyl cyclase-cAMP pathway, which molecule acts as the second messenger?

Accepted Answer

cAMP

Question 8

Which of the following best describes signal amplification in a signaling cascade?

Accepted Answer

One activated enzyme produces many molecules of a second messenger, amplifying the signal.

Question 9

Which of the following is an example of antagonistic control in cell signaling?

Accepted Answer

Insulin and glucagon regulating blood glucose levels in opposite directions.

Question 10

Which of the following is TRUE regarding the role of receptors in chemical signaling?

Accepted Answer

Receptors determine whether a cell will respond to a particular ligand.

Question 11

Which process describes the integration of multiple signals by a target cell?

Accepted Answer

Signal integration

Question 12

Which of the following is a characteristic of lipophobic ligands?

Accepted Answer

They bind to receptors located on the plasma membrane.

Question 13

Which of the following is an example of signal transduction?

Accepted Answer

A ligand binding to a receptor and activating a G-protein, which then activates adenylyl cyclase.

Question 14

What is the primary function of gap junctions in cell-to-cell communication?

Accepted Answer

To allow direct transfer of ions and small molecules between adjacent cells.

Question 15

Which of the following best describes the role of the endocrine system in long-distance communication?

Accepted Answer

It releases hormones into the bloodstream to affect distant target cells.

Question 16

Which of the following is an example of signal termination?

Accepted Answer

Destruction of second messengers after the signal has been transmitted.

Question 17

Which of the following is a correct sequence in the GPCR-adenylyl cyclase-cAMP pathway?

Accepted Answer

Ligand → GPCR → G-protein → Adenylyl cyclase → cAMP → Protein kinase A → Cellular response

Question 18

Which of the following is an example of contact-dependent signaling?

Accepted Answer

A cell presenting a membrane-bound ligand that binds to a receptor on an adjacent cell.

Question 19

Which of the following best describes the concept of specificity in receptor-ligand interactions?

Accepted Answer

Only ligands that physically fit in the binding site can activate the receptor.

Question 20

Which of the following is a plausible explanation for why a drug may lose effectiveness due to receptor saturation?

Accepted Answer

All available receptors are occupied, so increasing drug concentration does not increase the response.

Cell-to-Cell Communication in Anatomy & Physiology

Study Guide - Practice Questions