$$\text{G protein} + \text{GTP} \rightarrow \text{Active G protein}$$

Question 1

Which of the following best describes paracrine signaling?

Accepted Answer

A signal cell releases a regulator molecule that acts on nearby target cells, but not on itself.

Question 2

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

Accepted Answer

Endocrine signaling

Question 3

What is the primary function of G protein-coupled receptors (GPCRs) in cell signaling?

Accepted Answer

To transmit signals from extracellular molecules to intracellular effectors via G proteins

Question 4

Which of the following equations correctly represents the activation of a G protein?

Accepted Answer

$$	ext{G protein} + 	ext{GTP} ightarrow 	ext{Active G protein}$$

Question 5

Which of the following is a key difference between intracellular and extracellular (cell-surface) receptors?

Accepted Answer

Intracellular receptors bind hydrophobic signaling molecules that can cross the plasma membrane.

Question 6

What is the role of a phosphorylation cascade in cell signaling?

Accepted Answer

To amplify the signal by sequentially activating multiple protein kinases

Question 7

Which molecule acts as a second messenger in many signal transduction pathways?

Accepted Answer

Cyclic AMP ($$	ext{cAMP})$$

Question 8

During synaptic signaling, what is the main function of neurotransmitters?

Accepted Answer

To transmit signals across the synaptic cleft to the postsynaptic cell

Question 9

Which of the following best explains why only certain cells respond to a specific hormone?

Accepted Answer

Only cells with the appropriate receptor for the hormone will respond.

Question 10

What is apoptosis and why is it important for multicellular organisms?

Accepted Answer

It is programmed cell death that removes damaged or unnecessary cells, maintaining tissue health.

Question 11

Which of the following is NOT a stage of cell communication?

Accepted Answer

Replication

Question 12

Which type of receptor is most likely to bind a hydrophobic signaling molecule such as a steroid hormone?

Accepted Answer

Intracellular receptor

Question 13

What is the main function of ligand-gated ion channels in cell signaling?

Accepted Answer

To regulate the flow of specific ions across the plasma membrane in response to a signaling molecule

Question 14

Which of the following best describes the difference between cAMP and AMP?

Accepted Answer

cAMP has a cyclic structure and acts as a second messenger, while AMP is a nucleotide involved in energy metabolism.

Question 15

Which of the following equations represents the conversion of ATP to cAMP by adenylyl cyclase?

Accepted Answer

$$	ext{ATP} \xrightarrow{	ext{Adenylyl Cyclase}} 	ext{cAMP} + 	ext{PP}_i$$

Question 16

Which of the following is a real-world example of cell-to-cell recognition?

Accepted Answer

Glycoproteins on the surface of red blood cells determining blood type compatibility

Question 17

What is the result of a signal transduction pathway that activates transcription factors?

Accepted Answer

Regulation of gene expression, leading to the production of specific proteins

Question 18

Which of the following best explains the amplification of a cell signal by a phosphorylation cascade?

Accepted Answer

Each activated kinase phosphorylates many target proteins, increasing the overall response.

Question 19

Which of the following is most likely to occur if apoptosis is disrupted in a developing organism?

Accepted Answer

Abnormal tissue development, such as webbed fingers or toes

Cell Signaling and Communication: Study Notes for General Biology

Study Guide - Practice Questions