Question 1

Which of the following best describes the process of signal transduction in a cell?

Accepted Answer

A series of molecular interactions that relay signals from receptors to target molecules inside the cell, often amplifying the signal at each step.

Question 2

During the fight-or-flight response, epinephrine activates a signal transduction pathway in liver cells. Which secondary messenger is produced to activate protein kinase A?

Accepted Answer

cAMP (cyclic adenosine monophosphate)

Question 3

Which equation correctly represents the conversion catalyzed by adenylyl cyclase in the signal transduction pathway?

Accepted Answer

$$\mathrm{ATP} \rightarrow \mathrm{cAMP} + \mathrm{PP_i}$$

Question 4

What is the primary function of secondary messengers such as cAMP and Ca$$^{2+} in $$signal transduction pathways?

Accepted Answer

To amplify and distribute the initial signal within the cell, allowing for a coordinated cellular response.

Question 5

A mutation causes a cell to produce a defective protein kinase that cannot be phosphorylated. What is the most likely consequence for the cell’s signal transduction pathway?

Accepted Answer

The signal will not be amplified or properly relayed, resulting in a diminished or absent cellular response.

Question 6

Which of the following is a key difference between steroid hormones and peptide hormones in terms of their mode of action?

Accepted Answer

Steroid hormones are lipid-soluble and can pass through the cell membrane to bind intracellular receptors, while peptide hormones are water-soluble and bind to receptors on the cell surface.

Question 7

Which of the following best explains how caffeine keeps a person alert?

Accepted Answer

Caffeine binds to adenosine receptors on nerve cells but does not activate them, preventing the drowsiness signal from being transmitted.

Question 8

Which of the following events is an example of amplification in a signal transduction pathway?

Accepted Answer

One activated enzyme catalyzes the activation of many downstream molecules, increasing the number of products at each step.

Question 9

Which of the following is NOT a function of scaffold proteins in signal transduction?

Accepted Answer

Directly amplifying the signal by producing secondary messengers.

Question 10

A cell receives multiple signals at once. Which property of signal transduction pathways allows the cell to coordinate its response to these signals?

Accepted Answer

Pathway branching and cross-talk between different signaling pathways.

Question 11

Which of the following correctly describes the role of Ca$$^{2+}$$ ions in signal transduction?

Accepted Answer

Ca$$^{2+}$$ acts as a second messenger, triggering processes such as muscle contraction, secretion, and cell division.

Question 12

Which of the following mechanisms is used to 'turn off' a signal transduction pathway after the cell has responded?

Accepted Answer

Enzymatic breakdown or inhibition of activated proteins and secondary messengers.

Question 13

Which of the following is a real-world example of a signal transduction pathway affecting gene expression?

Accepted Answer

Steroid hormones such as estrogen enter the cell, bind to intracellular receptors, and regulate transcription of specific genes.

Question 14

Which of the following best describes the role of phosphorylation in signal transduction?

Accepted Answer

Phosphorylation activates or inhibits enzymes, allowing the cell to regulate its response to signals.

Question 15

Which of the following is a correct sequence of events in a G protein-linked receptor pathway?

Accepted Answer

Signal molecule binds to receptor $$\rightarrow G $$protein activated $$\rightarrow$$ Adenylyl cyclase activated $$\rightarrow$$ cAMP produced $$\rightarrow$$ Protein kinase A activated

Question 16

Which of the following is a plausible effect of a mutation that prevents the breakdown of cAMP in a cell?

Accepted Answer

Prolonged activation of protein kinase A, leading to excessive cellular responses.

Question 17

Which of the following is NOT a typical response of a cell to an environmental signal?

Accepted Answer

Permanent alteration of the cell’s DNA sequence.

Question 18

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

Accepted Answer

Each cell type has a unique collection of proteins that determine its specificity in detecting and responding to signals.

Question 19

Which of the following is a correct statement about the role of inositol triphosphate (IP$$_3) in $$signal transduction?

Accepted Answer

IP$$_3$$ acts as a second messenger that triggers the release of Ca$$^{2+}$$ from intracellular stores.

Question 20

Which of the following is a real-life example of a signal transduction pathway regulating a physiological process?

Accepted Answer

Insulin binding to its receptor on muscle cells, triggering a cascade that increases glucose uptake.

Cell Signal Transduction and Hormonal Regulation: Section 5.6 Study Notes

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드