Question

Extracellular signal molecules that are hydrophilic must bind to a cell-surface receptor in order to signal a target cell to change its behavior. These are examples of hydrophilic hormones in animals: A. tyrosine-derived epinephrin and norepinephrin B. insulin and glucagon C. serotonin and melatonin (tryptophan-derived mammalian neurotransmitters D. All of the above E. None of the above

Answer 1

Answer:

The correct answer is - D. all of the above.

Explanation:

Hydrophilic hormones are the hormones that can not pass through the cell membrane as they are poorly lipid-soluble and cannot pass through cell membranes and bind the receptors present on the surface of the membrane.  

Insulin and glucagon are peptide hormones that bind to a receptor in the target cell's membrane surface. Norepinephrine and epinephrine are catecholamines that are hydrophilic in nature.  Seratonin and Melatonin are also bound on the surface receptor due to their hydrophilic nature.