Q: Which of the following equations correctly represents the conversion of ATP to cAMP by adenylate cyclase?

$$\mathrm{ATP} \xrightarrow{\text{adenylate\ cyclase}} \mathrm{cAMP} + \mathrm{PP_i}$$

Question 1

Which of the following best describes the difference between endocrine and exocrine cells?

Accepted Answer

Endocrine cells release their secretions into the extracellular fluid, while exocrine cells secrete onto epithelial surfaces.

Question 2

Which hormone is classified as an amino acid derivative?

Accepted Answer

Epinephrine

Question 3

A patient is given a drug that inhibits adenylate cyclase. Which of the following hormone signaling pathways would be most directly affected?

Accepted Answer

The cAMP second messenger system

Question 4

Which of the following best explains why steroid hormones remain in circulation longer than peptide hormones?

Accepted Answer

Steroid hormones are bound to specific transport proteins in the blood.

Question 5

A hormone binds to a receptor on the plasma membrane of a target cell. Which of the following is the most likely sequence of events?

Accepted Answer

Activation of a G protein, production of a second messenger, activation of kinases, phosphorylation of proteins

Question 6

Which of the following is a correct example of negative feedback in endocrine regulation?

Accepted Answer

Increased blood glucose stimulates insulin release, which lowers blood glucose and reduces insulin secretion.

Question 7

Which of the following best describes the role of the hypothalamus in endocrine control?

Accepted Answer

It secretes regulatory hormones that control the anterior pituitary gland.

Question 8

A patient has a mutation that prevents the formation of G proteins in their cells. Which hormone signaling pathway would be most impaired?

Accepted Answer

Peptide hormones that use second messenger systems

Question 9

Which of the following is a peptide hormone produced by the pancreas?

Accepted Answer

Insulin

Question 10

Which of the following best explains why a hormone can have different effects in different tissues?

Accepted Answer

Different tissues have different receptors and intracellular proteins that respond to the hormone.

Question 11

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

Accepted Answer

$$\mathrm{ATP} \xrightarrow{	ext{adenylate\ cyclase}} \mathrm{cAMP} + \mathrm{PP_i}$$

Question 12

A researcher blocks the action of phosphodiesterase (PDE) in a cell. What is the most likely result?

Accepted Answer

Increased levels of cAMP and prolonged hormone signaling

Question 13

Which of the following hormones is produced by the adrenal medulla and is an amino acid derivative?

Accepted Answer

Epinephrine

Question 14

Which of the following best describes the mechanism of action for steroid hormones?

Accepted Answer

They diffuse through the plasma membrane and bind to intracellular receptors, altering gene transcription.

Question 15

A patient with a deficiency in transport proteins for thyroid hormones would most likely experience which of the following?

Accepted Answer

Decreased duration of thyroid hormone action in the blood

Question 16

Which of the following is an example of a hormone that uses a carrier-mediated transport process to enter its target cell?

Accepted Answer

Thyroid hormone

Question 17

Which of the following best explains the process of amplification in hormone signaling?

Accepted Answer

A small number of hormone molecules binding to membrane receptors leads to the formation of thousands of second messengers.

Question 18

Which of the following is a correct sequence of events for the action of a peptide hormone using the cAMP second messenger system?

Accepted Answer

Hormone binds to receptor → G protein activated → Adenylate cyclase activated → cAMP produced → Kinase activated

Question 19

Which of the following is a function of the hypothalamus in endocrine regulation?

Accepted Answer

Secretion of antidiuretic hormone (ADH) and oxytocin

Question 20

A patient is exposed to a drug that increases the activity of phosphodiesterase (PDE) in their cells. What is the most likely effect on hormone signaling that uses cAMP as a second messenger?

Accepted Answer

Decreased cAMP levels and reduced cellular response to the hormone

The Endocrine System: Structure, Function, and Regulation

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