7. A new compound synthesized in the lab acts on adrenergic receptors, which are

Question

7.

A new compound synthesized in the lab acts on adrenergic receptors, which are targets of epinephrine. In the presence of this compound, amylase production ceases. Which of the following would best describe the results/site of action of this compound?

A)

Increased levels of agonist

B)

Increases in cAMP

C)

Decreases in fluid secretion

D)

-epinephrine antagonist receptor

E)

-epinephrine antagonist receptor

8.

When the output of a ________ is detected by a sensor and leads to more output, this is called __________ .

A)

sensor; positive feedback

B)

controller; redundancy

C)

sensor; negative feedback

D)

controller; positive feedback

E)

sensor; homeostasis

7.

A new compound synthesized in the lab acts on adrenergic receptors, which are targets of epinephrine. In the presence of this compound, amylase production ceases. Which of the following would best describe the results/site of action of this compound?

A)

Increased levels of agonist

B)

Increases in cAMP

C)

Decreases in fluid secretion

D)

-epinephrine antagonist receptor

E)

-epinephrine antagonist receptor

Explanation / Answer

First question Answer: Option E

Epinephrine stimulates the secretion of amylase and this can happen only when epinephrine binds to its adrenergic receptors. Now, since the new compound binds to adrenergic receptors, less of epinephrine can bind to adrenergic receptors causing the amylase levels to go down and hence acts as antagonists. Since amylase levels are reduced, option A can be taken off the list. Also, Increases in cAMP is a result of epinephrine binding to receptors so option B can also be taken off. Since beta receptors are involved in epinephrine stimulated secretion of amylase, I would go with option E -epinephrine antagonist receptor.

Second question Answer: Option A.

Explanation: First let's see what positive feedback means. They are a change in a given direction that causes an additional change in the same direction. As an example, an increase of the concentration of a substance causes feedback that produces continued increases in concentration which is nothing but "output leading to more output" in the question. So Options B, D, and E can be excluded. Between Option A and D, I would go with sensor as it makes more sense with respect to how positive feedback works. To explain, let's take the example of blood clotting which is a positive feedback reaction. An injured tissue releases signal chemicals that activate platelets in the blood which in turn activates more platelets. So, the first platelets activated is "output of sensors" which when detected by sensors produce more platelets causing positive feedback. So, I would go with option A.

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