Which of the following correctly describes the role of cAMP and the hormones employing it?
1. binding site; nonsteroid
2. membrane receptor; steroid
3. activity site; G protein
4. second messenger; nonsteroid
Hydrophilic hormones are not characterized by the fact that:
1. They can act through intermediary G proteins.
2. A second messenger (e.g. cAMP) is often involved.
3. They can work by activation of transmembrane receptor proteins.
4. They have a long duration of action (e.g. days).
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R):
Assertion (A): | For steroid or thyroid hormones, their receptors are located inside the cell of the target cell. |
Reason (R): | To bind their receptors, these hormones must first cross the cell membrane. |
In the light of the above statements choose the correct answer from the options given below:
1. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are true but (R) is not the correct explanation of (A). |
3. | (A) is true but (R) is false. |
4. | Both (A) and (R) are false. |