Teaching MPPSC Assistant Professor Mock Test Series 2025 Life Sciences Cell Communication and Cell Signaling
G protein-coupled receptors (GPCRs) are used to detect and respond to many different types of signals, including neurotransmitters, hormones involved in glycogen and fat metabolism and even photons of light.
Which one of the following statements regarding GPCR is INCORRECT?
1
GPCRs are a large family with a common structure of seven membrane spanning a helices.
2
GPCRs are coupled to trimeric G proteins comprising three subunits α, β and γ
3
The Ga subunit is a GTPase switch protein that alternates between an active ('on') state with bound GTP and an inactive (off) state with GDP.
4
The 'on' form gets bound to β and γ subunits and activates a membrane- bound effector like adenylyl cyclase, phospholipase C or ion channel.