Quiz 8

Question 1

Phosphorylation of proteins is through what kind of chemical bonding?

Answer 1

covalent bond

Question 2

What is the most likely mechanism by which testosterone functions inside a cell?

Answer 2

It binds with a receptor protein that enters the nucleus and activates expression of specific genes.

Question 3

What role do phosphatases play in signal transduction pathways?

Answer 3

They inactivate protein kinases to turn off signal transduction.

Question 4

What is the most likely reason two different types of cells may respond differently to the same steroid hormone?

Answer 4

The receptors create different cascades of secondary messengers

Question 5

Caffeine is an inhibitor of phosphodiesterase. Therefore, the cells of a person who has recently consumed coffee would have increased levels of which of the following molecules?

Answer 5

cAMP

Question 6

Some hormones bind to membrane receptors and others bind to intracellular receptors. Hormones that bind to extracellular membrane receptors tend to be:

Answer 6

Hydrophilic

Question 7

Protein kinase is an enzyme that functions in which of the following ways?

Answer 7

Activates or inactivates other proteins by adding a phosphate group to them

Question 8

If a cell that normally produces paracrine signals is unable to produce signals during development, which cells will be most affected?

Answer 8

Cells that are nearby but not in contact with the signaling cell’s membrane

Question 9

Hormones are chemical substances produced in one organ that are released into the bloodstream and affect the function of a target organ. Which of the following conditions is required for the target organ to respond to a particular hormone?

Answer 9

The target organ must have receptors that recognize and bind the hormone molecule.

Question 10

The activity of adenylyl cyclase is essentially the opposite of which of the following enzymes?

Answer 10

Phosphodiesterase