Question 1

Which of the following best describes the difference between local and long-distance cell-to-cell communication in the human body?

Accepted Answer

Local communication involves direct contact or diffusion to nearby cells, while long-distance communication uses the circulatory system or neurons to reach distant targets.

Question 2

A patient is given a drug that acts as an antagonist to a specific receptor. What is the most likely effect of this drug?

Accepted Answer

It will bind to the receptor and block the primary ligand from binding, preventing the normal response.

Question 3

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

Accepted Answer

Receptor activation → Second messenger production → Target protein modification → Cellular response

Question 4

Which type of receptor is most likely to mediate the fastest cellular responses?

Accepted Answer

Chemically gated (ligand-gated) ion channels

Question 5

A lipophilic hormone is most likely to:

Accepted Answer

Diffuse through the cell membrane and bind to an intracellular receptor, often affecting gene expression.

Question 6

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

Accepted Answer

A single extracellular signal leads to the production of many intracellular second messengers, greatly increasing the response.

Question 7

Which second messenger is produced from ATP by the action of adenylyl cyclase?

Accepted Answer

cAMP

Question 8

Nitric oxide (NO) is an example of a signal molecule that:

Accepted Answer

Is a short-acting paracrine that causes vasodilation by diffusing into smooth muscle.

Question 9

Which of the following best describes the role of calcium ions ($$\mathrm{Ca$$^{2+}$$}) as a $$second messenger?

Accepted Answer

$$\mathrm{Ca$$^{2+}$$}$$ enters the cytosol through gated channels and binds to proteins like calmodulin, altering their activity.

Question 10

A researcher observes that a cell decreases its response to a constant concentration of a hormone over time. Which process best explains this observation?

Accepted Answer

Down-regulation of receptors

Question 11

Which of the following is true regarding the specificity of ligand-receptor interactions?

Accepted Answer

A ligand will only bind to receptors with a specific shape and chemical properties.

Question 12

Epinephrine can cause blood vessels to either constrict or dilate depending on the type of adrenergic receptor present. This is an example of:

Accepted Answer

Target cell response depending on receptor type

Question 13

Which of the following best describes the difference in how the nervous and endocrine systems code for stimulus intensity?

Accepted Answer

The nervous system codes intensity by action potential frequency, while the endocrine system codes by the amount of hormone released.

Question 14

Which of the following is a correct example of a homeostatic reflex pathway?

Accepted Answer

Stimulus → Sensor → Input signal → Integrating center → Output signal → Target → Response

Question 15

A patient is given a beta-blocker to reduce blood pressure. This drug most likely acts by:

Accepted Answer

Blocking adrenergic receptors, preventing epinephrine from binding.

Question 16

Which of the following is NOT a typical effect of activating a G protein-coupled receptor (GPCR)?

Accepted Answer

Directly phosphorylating proteins without second messengers

Question 17

Which of the following best describes the role of cytokines in cell signaling?

Accepted Answer

Cytokines are peptides that can act as both local (autocrine/paracrine) and long-distance signals, especially in immune responses.

Question 18

Which of the following is a correct statement about the arachidonic acid cascade?

Accepted Answer

Arachidonic acid is produced from membrane phospholipids and can be converted into eicosanoids such as prostaglandins and leukotrienes.

Question 19

Which of the following is an example of competition in ligand-receptor interactions?

Accepted Answer

Epinephrine and norepinephrine both binding to adrenergic receptors.

Question 20

Which of the following best describes the effect of a ligand binding to an integrin receptor?

Accepted Answer

It alters enzymes or the cytoskeleton, affecting cell shape or movement.

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

Study Guide - Practice Questions

Study Guide - Flashcards