PATHOLOGY

Detailed explanation-1: -The amino acid-derived hormones epinephrine and norepinephrine bind to beta-adrenergic receptors on the plasma membrane of cells. Hormone binding to receptor activates a G-protein, which in turn activates adenylyl cyclase, converting ATP to cAMP.

Detailed explanation-2: -A meaningful receptor–ligand interaction leads to a physiological response. For example, when glucagon binds to its receptor on adipocytes, the production of fatty acids by hydrolysis of triacylglycerols is enhanced.

Detailed explanation-3: -Describes cells that have a group of proteins that bind to a specific hormone. For example, some breast cancer cells have receptors for the hormones estrogen or progesterone. These cells are hormone receptor positive and they need estrogen or progesterone to grow.

Detailed explanation-4: -A ligand that can bind to and alter the function of the receptor that triggers a physiological response is called a receptor agonist. Ligands that bind to a receptor but fail to activate the physiological response are receptor antagonists.