Why are g-protein coupled receptors often known as 7tm receptors? a. they have 7 transmembrane β-pleated sheets. b. they have 7 transmembrane α-helices. c. they have 7 tyrosine-methionine dipeptides in their structure. d. they have 7 methionine-tryptophan dipeptides in their structure.

B

Explanation:

G protein-coupled receptors (GPCRs), also known as seven-(pass)-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptor, and G protein–linked receptors (GPLR),comprises of a large protein family of receptors that discover molecules outside the cell and initiate internal signal transduction pathways and, eventually, cellular responses. They are called seven-transmembrane receptors because they pass through the cell membrane seven times

c

explanation:

i think

answer:   option a) glucagon was secreted by his pancreas before he ate the cookies because blood glucose was low. insulin was secreted after he ate the cookies because his blood glucose was high.

explanation: