Question

Put the following steps of trimeric G-protein activation in order. Note: (GPCR = G-protein coupled receptor)

A. G-protein dissociates into alpha and beta-gamma subunits
B. series of cascade effects are initiated within the cell
C. signal molecule binds to and activates the GPCR
D. G-protein alpha subunit finds and activates target protein
E. GPCR causes conformational change in G-protein alpha subunit, causing release of GDP and binding of GTP)
A) C, E, A, B, D
B) C, A, E, D, B
C) A, C, E, B, D
D) E, C, A, B, D

Answer 1

The correct sequence for G-protein activation initiated by a GPCR involves the binding of a signal molecule to the GPCR, a conformational change leading to GDP-GTP exchange in the alpha subunit, dissociation of subunits, activation of target proteins by the alpha subunit, and initiation of a signalling cascade within the cell.

Step-by-step explanation:

The correct order of the steps for trimeric G-protein activation is as follows:

Signal molecule binds to and activates the GPCR (the G-protein-coupled receptor).

The GPCR causes conformational change in G-protein alpha subunit, causing release of GDP and binding of GTP.

The G-protein dissociates into alpha and beta-gamma subunits.

The G-protein alpha subunit finds and activates target protein.

A series of cascade effects are initiated within the cell.