Question

(1) Which 2 of the following hormones "Response to Receptor-Ligand Binding" is dependent upon the activation of second messenger systems?

(2) Which 2 for activation of genes for transcription and translation?

-Peptide Hormones
-Steroid Hormones
-Catecholamines
-Thyroid Hormones

Answer 1

Peptide Hormones and Catecholamines use second messenger systems like cAMP, whereas Steroid Hormones and Thyroid Hormones affect gene expression directly within the target cell's nucleus for transcription and translation.

Step-by-step explanation:

The hormones that depend on the activation of second messenger systems when they bind to cell surface receptors are Peptide Hormones and Catecholamines. These hormones, such as epinephrine and norepinephrine, use a secondary messenger like cyclic AMP (cAMP) to amplify the hormonal signal within the cell. When these hormones bind to their receptors, it activates a G-protein, which in turn activates an enzyme called adenylyl cyclase, converting ATP to cAMP. This process leads to a series of cellular responses including protein phosphorylations.

On the other hand, Steroid Hormones and Thyroid Hormones induce effects by activating genes for transcription and translation. These hormones can cross the cell membrane due to their lipophilic nature and bind to internal receptors, forming a hormone-receptor complex that affects gene expression directly within the nucleus of the target cell.