A typical prokaryotic cell has about 3,000 genes in its DNADNA, while a human cell has about 21,300 genes. About 1,000 of these genes are present in both types of cells. How do you explain how such different organisms could have this same subset of 1,000 genes

located... on the plasma membrane  

is considered... inactive

the messenger is considered... to be active

All of this is brought on by a signal molecule

will shut down quickly when the signal molecule

Explanation:

The G protein-coupled receptors (GPCRs) are transmembrane proteins found on the plasma membrane. GPCRs are considered to be the most diverse group of transmembrane receptors in eukaryotic cells. These proteins (GPCRs) bind to signaling molecules to trigger signaling pathways through Guanine nucleotide-binding proteins (G-proteins). G proteins are signaling proteins (for example, Ras protein) that bind both GTP and GDP. After the signaling molecule binds to GPCR, GTP is hydrolyzed by the G-protein in a process that triggers specific signaling pathways (for example, activation of the production of second messengers).