Question 1

Which of the following best describes how steroid hormones typically exert their effects on target cells?

Accepted Answer

They enter the cell by diffusion, bind to intracellular receptors, and stimulate gene expression.

Question 2

A patient is given a drug that blocks beta-adrenergic receptors in the heart. What is the most likely physiological effect?

Accepted Answer

Decreased heart rate due to inhibition of adrenaline/epinephrine signaling.

Question 3

Which of the following statements about hormone target cells is correct?

Accepted Answer

Only cells with specific receptors for a hormone will respond to that hormone.

Question 4

Nonsteroid hormones typically cannot cross the cell membrane. How do they exert their effects?

Accepted Answer

By binding to receptors on the cell surface and initiating a signaling cascade.

Question 5

Which process is responsible for amplifying a signal many times during a phosphorylation cascade?

Accepted Answer

Protein kinases adding phosphate groups to multiple target proteins.

Question 6

A cell is exposed to constant stimulation by a signaling molecule. What is a likely cellular response regarding its receptors?

Accepted Answer

The number of receptors may decrease, reducing sensitivity to the signal.

Question 7

Which of the following is a correct sequence of events for signal transduction involving a nonsteroid hormone?

Accepted Answer

Hormone binds to cell surface receptor $$\rightarrow$$ activation of second messenger $$\rightarrow$$ protein kinase activation.

Question 8

Which enzyme is responsible for ending a phosphorylation cascade by removing phosphate groups from proteins?

Accepted Answer

Phosphatase

Question 9

Quorum sensing in bacteria is an example of which type of cell communication?

Accepted Answer

Cell-cell signaling based on population density.

Question 10

Which of the following best explains why many drugs target G-protein coupled receptors?

Accepted Answer

G-protein coupled receptors are involved in a large number of signaling pathways and are accessible on the cell surface.

Question 11

Which of the following is a real-world consequence of disrupted cell signaling in the intestine?

Accepted Answer

Diarrhea and dehydration due to altered ion flow.

Question 12

Which statement about protein kinases is correct?

Accepted Answer

Protein kinases add phosphate groups to proteins, activating or inactivating them.

Question 13

A mutation causes a cell to produce nonfunctional phosphatases. What is the most likely effect on signal transduction?

Accepted Answer

Phosphorylation cascades will be prolonged, potentially leading to excessive cellular responses.

Question 14

Which of the following is true about the diversity of signal transduction pathways?

Accepted Answer

Signal transduction pathways can be diversified and have multiple effects depending on the cell type and context.

Question 15

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

Accepted Answer

Second messengers are small molecules or ions that relay signals inside the cell, often activating protein kinases.

Question 16

Which of the following best explains why receptors are described as 'not static'?

Accepted Answer

The number and sensitivity of receptors can change over time, especially with constant stimulation.

Question 17

Which of the following is a correct example of crosstalk in cell signaling?

Accepted Answer

Multiple signaling pathways interacting and integrating information, similar to a network in a computer.

Question 18

Which of the following is a correct statement about the action of adrenaline (epinephrine) in different tissues?

Accepted Answer

Adrenaline can have different effects depending on the receptors present in each tissue, such as the liver versus the heart.

Question 19

Which of the following equations correctly represents the action of a protein kinase in a phosphorylation cascade?

Accepted Answer

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

Question 20

Which of the following best describes the role of carrier proteins in steroid hormone signaling?

Accepted Answer

Carrier proteins transport steroid hormones through the blood to target cells.

Cell Signaling and Communication in General Biology

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