Question 1

Which of the following correctly describes the sequence of events for cortisol signaling via intracellular receptors?

Accepted Answer

Cortisol passes through the plasma membrane, binds to an intracellular receptor, the complex enters the nucleus, binds to DNA, and acts as a transcription factor.

Question 2

Which property allows cortisol to pass through the plasma membrane?

Accepted Answer

It is a small, nonpolar, hydrophobic molecule.

Question 3

After cortisol binds to its intracellular receptor, what is the next step in the signaling pathway?

Accepted Answer

The cortisol-receptor complex acts as a transcription factor in the nucleus.

Question 4

Which of the following is TRUE about the histamine H$$_1$$ receptor signaling pathway?

Accepted Answer

Histamine binds extracellularly to the H$$_1$$ receptor, which is a G protein-coupled receptor.

Question 5

What is the role of the G protein in the histamine H$$_1$$ receptor pathway?

Accepted Answer

It activates the enzyme phospholipase C after being activated by the receptor.

Question 6

Which of the following best explains why histamine cannot pass through the plasma membrane?

Accepted Answer

Histamine is highly hydrophilic and charged.

Question 7

A patient is given a drug that blocks phospholipase C. What effect would this have on histamine H$$_1$$ receptor signaling?

Accepted Answer

The downstream signaling cascade would be inhibited after G protein activation.

Question 8

Which of the following steps is NOT involved in the signaling pathway of cortisol with intracellular receptors?

Accepted Answer

Cortisol binds to a G protein-coupled receptor on the cell surface.

Question 9

Which of the following best describes the difference between the signaling mechanisms of cortisol and histamine?

Accepted Answer

Cortisol acts as a transcription factor after binding its receptor, while histamine activates a G protein-coupled receptor pathway.

Question 10

A mutation causes the H$$_1$$ receptor to lose its ability to undergo a conformational change after histamine binding. What is the most likely consequence?

Accepted Answer

The G protein will not be activated, and downstream signaling will not occur.

Question 11

Which of the following equations best represents the binding of a ligand (L) to its receptor (R) to form a ligand-receptor complex (LR)?

Accepted Answer

$$L + R \rightarrow LR$$

Question 12

In the context of allergic responses, why is the activation of phospholipase C significant after histamine binds to the H$$_1$$ receptor?

Accepted Answer

It leads to the production of second messengers that amplify the inflammatory response.

Question 13

Which of the following is a direct result of the cortisol-receptor complex binding to DNA in the nucleus?

Accepted Answer

Activation or repression of specific gene transcription.

Question 14

A researcher is studying a new hormone that is hydrophilic and cannot cross the plasma membrane. Which type of receptor is this hormone most likely to use?

Accepted Answer

A G protein-coupled receptor on the cell surface.

Question 15

Which of the following best explains why steroid hormones like cortisol can act as transcription factors?

Accepted Answer

They form complexes with intracellular receptors that can enter the nucleus and bind DNA.

Cell Signaling: Steroid Hormones and G Protein-Coupled Receptors

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