Question

Question 31 would lead to an action potential in a ganglion cell. Depolarization of a rod cell CGMP binding to cGMP gated Na+ channels Rods releasing Inhibitory neurotransmitters Transducinactivating PDE Retinal reverting to its inactive state

Answer 1

Ans31)Transducin activating PDE

Explaination:Depolarisation of a rod cell occurs in ie, rods releasing inhibitory neurotransmitters which is result of cGMP binding to cGMP gated Na+ channels .In dark retinal remain in inactive state.

And depolarisation of rod cell leads to hyperpolarisation pf ganglion cell.

In light Rod cell become hyperpolarised due to structural change in retinal from inactive to active form, their affinity for transducin ie, G protein increases and leads to replacement of GDP with GTP at alpha subunit of Gprotein (transducin) which leads to dissociation of alpha subunit from beta and gamma subunit of transducin G protein and this free alpha sununit binds with cGMP phosphodiesterase(PDE) and activate it. On activation PDE catalysed the the cGMP hydrolyzing reaction and break down it into 5'-GMP.This leads to decrease in concentration of cGMP resting in hyperpolarisation of Rod cell membrane which prevent release of inhibitory neurotransmitters and leads to depolarisation of ganglion cell ie, development of action potential in ganglion cell.