Question 1

Steroid hormones exert their effects in target cells by binding to which type of receptor, and what is the primary function of this receptor?

Accepted Answer

Nuclear receptors; act as transcriptional regulators to modulate gene expression

Question 2

Nitric oxide (NO) induces smooth muscle relaxation by binding to which enzyme, and what is the product of this reaction?

Accepted Answer

Guanylyl cyclase; produces cyclic GMP ($$cGMP)$$

Question 3

Which of the following is NOT a type of cell surface receptor?

Accepted Answer

Signal coupled receptor

Question 4

Ion channel coupled receptors are primarily responsible for which cellular function?

Accepted Answer

Responding to electrical gradients across membranes

Question 5

Which of the following is NOT a classification of signaling molecules based on their mode of action?

Accepted Answer

Lynocrine

Question 6

True or False: Signaling molecules work only through signaling cascades.

Accepted Answer

False

Question 7

G-protein coupled receptors (GPCRs) are characterized by which structural feature?

Accepted Answer

Seven transmembrane alpha helices

Question 8

Which statement about cAMP levels in cells is correct?

Accepted Answer

cAMP levels are kept at low concentrations in the cell

Question 9

Inositol phospholipid signaling pathways are activated by GPCRs and result in the cleavage of PIP2 into which two second messengers?

Accepted Answer

IP3 and DAG

Question 10

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

Accepted Answer

Binds calcium, undergoes conformational change, and regulates other proteins

Question 11

A cell receives a signal from a neurotransmitter that binds to a receptor, causing an influx of Na+ ions and a change in membrane potential. Which receptor type is most likely involved?

Accepted Answer

Ion channel coupled receptor

Question 12

Which of the following is a correct sequence for the activation of a nuclear receptor by a steroid hormone?

Accepted Answer

Steroid hormone enters the cell, binds to nuclear receptor, triggers conformational change, and regulates gene expression

Question 13

Which signaling molecule is classified as a gas and can act as a paracrine signal to cause muscle relaxation?

Accepted Answer

Nitric oxide (NO)

Question 14

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

Accepted Answer

They relay signals from receptors to target molecules inside the cell

Question 15

A mutation prevents the activation of adenylyl cyclase by G proteins. Which cellular process would be most directly affected?

Accepted Answer

Production of cyclic AMP ($$cAMP)$$

Question 16

Which equation correctly represents the formation of cyclic GMP ($$cGMP) $$from GTP by guanylyl cyclase?

Accepted Answer

$$GTP \rightarrow cGMP + PP_i$$

Question 17

Which of the following is a function of endocrine signaling molecules?

Accepted Answer

Transported through the circulatory system to distant cells

Question 18

Which of the following statements about GPCR desensitization is correct?

Accepted Answer

Desensitization blocks active receptors from activating G proteins

Question 19

Which of the following best explains why different cell types can respond differently to the same signaling molecule?

Accepted Answer

Different cell types express different receptors and downstream signaling proteins

Cell Signaling Mechanisms and Receptors: Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard