he G-protein-linked receptor is located . When GDP is attached to the G protein the messenger is considered . GTP replaces GDP and now the messenger is considered . The G protein carrying the GTP leaves the receptor and and enzyme which causes a cellular response. All of this is brought on by a attaching to the G-protein-linked receptor and will shut down quickly when the is no longer there.

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).