This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of nucleic acids, Subject name: Biochemistry
True about G-protein receptor complex 
Select and explain. 
A. It interacts transmembrane domain, B. GTP to GDP, C. Adenyl cyclase activation leads to increased cAMP, D. GPCR has no phosphorylation propey
A: It interacts transmembrane domain
Answer: A: It interacts transmembrane domain 
Explanation: G protein-coupled receptors (GPCRs) which are also known as seven-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptor, and G protein-linked receptors (GPLR), constitute a large protein family of receptors, that sense molecules outside the cell and activate inside signal transduction pathways and, ultimately, cellular responses.Coupling with G proteins, they are called seven-transmembrane receptors because they pass through the cell membrane seven times.