Question 1

Which of the following best describes the role of gap junctions in cell-to-cell communication?

Accepted Answer

They allow direct cytoplasmic exchange of ions and small molecules between adjacent cells.

Question 2

A lipophilic signal molecule is most likely to:

Accepted Answer

Bind to a receptor located inside the cell, such as a cytosolic or nuclear receptor.

Question 3

Which of the following is TRUE regarding cytokines compared to classical hormones?

Accepted Answer

Cytokines can be produced by any nucleated cell and are made on demand.

Question 4

Which equation best represents the conversion catalyzed by guanylyl cyclase in signal transduction?

Accepted Answer

$$GTP \rightarrow cGMP$$

Question 5

A patient is given a drug that acts as a receptor antagonist. What is the most likely effect?

Accepted Answer

The drug will block receptor activity, preventing the normal cellular response.

Question 6

Which of the following is a correct sequence for a typical signal transduction pathway?

Accepted Answer

Ligand binds receptor $$\rightarrow$$ receptor activates intracellular signal molecules $$\rightarrow$$ cellular response

Question 7

Which of the following is a function of prostaglandins, a type of eicosanoid?

Accepted Answer

Regulation of sleep, inflammation, pain, and fever

Question 8

Which of the following best explains the concept of signal amplification in cellular signaling?

Accepted Answer

One ligand binding event can activate multiple intracellular molecules, resulting in a large cellular response.

Question 9

Which of the following is a correct description of tonic control in homeostatic reflex pathways?

Accepted Answer

A single parameter is regulated by varying the amount of neural input, not by switching on and off.

Question 10

Which of the following is a rapid signal pathway found primarily in nerve and muscle cells?

Accepted Answer

Ligand binding to receptor-channel proteins that change ion permeability

Question 11

A researcher observes that a cell increases the number of receptors on its surface in response to low ligand concentration. This is an example of:

Accepted Answer

Up-regulation

Question 12

Which of the following molecules is produced by endothelial cells, diffuses into smooth muscle, and causes vasodilation?

Accepted Answer

Nitric oxide (NO)

Question 13

Which of the following is the first step in the arachidonic acid cascade?

Accepted Answer

Breakdown of phospholipid by phospholipase A2 (PLA2)

Question 14

Which of the following is a correct comparison between neural and endocrine control systems?

Accepted Answer

Neural control is faster and more specific than endocrine control.

Question 15

Which of the following is a function of integrin receptors?

Accepted Answer

They transfer information from the extracellular matrix to the cytoskeleton.

Question 16

Which of the following best describes the role of calcium ($$Ca^{2+}) as an $$intracellular signal?

Accepted Answer

It binds to calmodulin or other regulatory proteins to trigger cellular responses.

Question 17

Which of the following is a correct example of antagonistic control in physiology?

Accepted Answer

The sympathetic and parasympathetic nervous systems have opposite effects on heart rate.

Question 18

Which of the following is a plausible effect of NSAIDs (nonsteroidal anti-inflammatory drugs) on eicosanoid signaling?

Accepted Answer

NSAIDs inhibit cyclooxygenase (COX), reducing prostaglandin synthesis and inflammation.

Question 19

Which of the following is a correct description of the GPCR-adenylyl cyclase signal transduction pathway?

Accepted Answer

Ligand binding activates a G protein, which stimulates adenylyl cyclase to convert $$ATP to$$ $$cAMP.$$

Question 20

A cell exposed to a high concentration of ligand for a prolonged period may decrease its number of surface receptors. This process is called:

Accepted Answer

Down-regulation

Chapter 6: Communication, Integration, and Homeostasis – Study Notes

Study Guide - Practice Questions