Q: Which equation correctly represents the conversion of ATP to cAMP by adenylyl cyclase?

$$\mathrm{ATP} \xrightarrow{\text{adenylyl\ cyclase}} \mathrm{cAMP} + \mathrm{PP_i}$$

Question 1

Which of the following best describes the sequence of events in cell signaling, as illustrated by the impala's response to a cheetah?

Accepted Answer

Signal reception → Signal transduction → Cellular response

Question 2

Which type of cell signaling involves hormones traveling through the bloodstream to reach distant target cells?

Accepted Answer

Endocrine signaling

Question 3

A signaling molecule binds to a G protein-coupled receptor (GPCR) on the cell membrane. What is the immediate next step in the signaling pathway?

Accepted Answer

The G protein exchanges GDP for GTP

Question 4

Which of the following is a correct description of a second messenger in cell signaling?

Accepted Answer

A small, water-soluble molecule or ion that rapidly diffuses inside cells

Question 5

In the GPCR pathway, which enzyme is responsible for converting ATP to cAMP?

Accepted Answer

Adenylyl cyclase

Question 6

Which equation correctly represents the conversion of ATP to cAMP by adenylyl cyclase?

Accepted Answer

$$\mathrm{ATP} \xrightarrow{	ext{adenylyl\ cyclase}} \mathrm{cAMP} + \mathrm{PP_i}$$

Question 7

A mutation causes a receptor tyrosine kinase (RTK) to be permanently active, even without ligand binding. What is a likely consequence?

Accepted Answer

The cell may undergo uncontrolled division, potentially leading to cancer

Question 8

Which of the following best explains why the same hormone (such as epinephrine) can produce different responses in different tissues?

Accepted Answer

Different tissues express different receptors or signaling pathways

Question 9

Which of the following is a rapid cellular response to a signal, as opposed to a slower response?

Accepted Answer

Phosphorylation of an existing protein to change its activity

Question 10

Which of the following best describes the function of a ligand-gated ion channel?

Accepted Answer

It opens to allow ions to flow across the membrane when a ligand binds

Question 11

A steroid hormone like aldosterone binds to its receptor inside the cell. What is the most likely result of this binding?

Accepted Answer

The hormone–receptor complex acts as a transcription factor to change gene expression

Question 12

Which of the following best explains the importance of signal termination in hormonal signaling?

Accepted Answer

It prevents over-correction and maintains homeostasis

Question 13

Which of the following is a correct statement about apoptosis?

Accepted Answer

It is a programmed process that safely dismantles and removes damaged or unnecessary cells

Question 14

Which of the following best describes the role of kinases and phosphatases in signal transduction?

Accepted Answer

Kinases add phosphate groups to proteins, while phosphatases remove them

Question 15

A patient has a mutation that prevents the production of cAMP in response to epinephrine. Which step in the signaling pathway is most likely disrupted?

Accepted Answer

Activation of adenylyl cyclase

Question 16

Which of the following equations represents the breakdown of cAMP to AMP by phosphodiesterase?

Accepted Answer

$$\mathrm{cAMP} + \mathrm{H_2O} \xrightarrow{	ext{phosphodiesterase}} \mathrm{AMP}$$

Question 17

Which of the following scenarios best illustrates the concept of signal amplification in a signaling pathway?

Accepted Answer

One hormone molecule triggers the activation of thousands of enzyme molecules, leading to a large cellular response

Question 18

Which of the following is an example of a negative feedback mechanism in hormonal regulation?

Accepted Answer

High blood glucose stimulates insulin release, which lowers blood glucose and then reduces insulin secretion

Question 19

Which of the following best describes the role of apoptosis during development?

Accepted Answer

It removes unnecessary cells, such as those between developing fingers and toes

Cell Communication and Signaling Pathways: Study Notes for General Biology

Guida di studio - Domande di pratica

Study guide - Flashcard