$$\text{Protein} + \text{ATP} \rightarrow \text{Protein-P} + \text{ADP}$$

Question 1

Which of the following best describes the role of epinephrine in the impala's flight response when chased by a cheetah?

Accepted Answer

Epinephrine is a hormone that initiates a signal transduction pathway, leading to the breakdown of glycogen in muscle cells.

Question 2

Which of the following is the correct sequence of events in cell signaling as illustrated by the impala's response to danger?

Accepted Answer

Signal reception → Signal transduction → Cellular response

Question 3

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

Accepted Answer

They transmit signals from extracellular signaling molecules to intracellular relay molecules.

Question 4

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

Accepted Answer

Endocrine signaling

Question 5

Gap junctions in animal cells and plasmodesmata in plant cells are examples of which type of cell communication?

Accepted Answer

Direct contact signaling through cell junctions

Question 6

Which of the following best explains why only certain cells respond to a particular signaling molecule?

Accepted Answer

Only cells with a receptor specific to the signaling molecule can respond.

Question 7

A scientist observes that a signaling molecule binds to a receptor, causing the receptor to change shape. What is this process called?

Accepted Answer

Reception

Question 8

Which of the following is a common feature of signal transduction pathways?

Accepted Answer

They often include a phosphorylation cascade involving protein kinases.

Question 9

What is the role of second messengers such as cyclic AMP ($$cAMP) in $$cell signaling?

Accepted Answer

They transmit signals from the cell surface to intracellular targets, amplifying the response.

Question 10

Which equation correctly represents the phosphorylation of a protein by a kinase during signal transduction?

Accepted Answer

$$	ext{Protein} + 	ext{ATP} ightarrow 	ext{Protein-P} + 	ext{ADP}$$

Question 11

A mutation prevents the formation of active adenylyl cyclase in muscle cells. What is the most likely consequence for the impala during a chase?

Accepted Answer

The muscle cells will be unable to break down glycogen efficiently.

Question 12

Which of the following best describes the function of a ligand in cell signaling?

Accepted Answer

A ligand is a molecule that binds specifically to a receptor to initiate a cellular response.

Question 13

Which scenario illustrates paracrine signaling?

Accepted Answer

A cell releases growth factors that affect nearby cells in the same tissue.

Question 14

Which of the following is NOT a typical cellular response to a signal transduction pathway?

Accepted Answer

Direct synthesis of ATP from glucose

Question 15

Which of the following statements about receptor tyrosine kinases is correct?

Accepted Answer

They are plasma membrane receptors that phosphorylate themselves and relay proteins upon ligand binding.

Question 16

In the context of cell signaling, what is the main difference between local and long-distance signaling?

Accepted Answer

Local signaling affects nearby cells, while long-distance signaling affects cells throughout the organism.

Question 17

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

Accepted Answer

Each activated kinase can activate many downstream kinases, multiplying the signal.

Question 18

Which of the following is a real-world example of synaptic signaling?

Accepted Answer

A neuron releasing acetylcholine to stimulate a muscle cell.

Question 19

Which of the following is most likely to occur if a cell lacks the specific receptor for a signaling molecule?

Accepted Answer

The cell will ignore the signal and show no response.

Question 20

Which process is illustrated by the breakdown of glycogen to glucose in muscle cells during the impala's escape?

Accepted Answer

Cellular response to a signal transduction pathway

Cell Communication and Signal Transduction in Biology

Study Guide - Practice Questions