The presence of cGMP in the cytosol of a photoreceptor will directly stimulate the
A) closure of potassium channels.
B) opening of sodium channels.
C) closure of sodium channels.
D) opening of potassium channels.
E) opening of calcium channels.

Question

Quizplus · Accepted Answer

The presence of cGMP in the cytosol of a photoreceptor directly stimulates the opening of sodium channels. This is a key step in the phototransduction cascade, where light leads to a decrease in cGMP levels, causing sodium channels to close and the photoreceptor to hyperpolarize.

The Presence of CGMP in the Cytosol of a Photoreceptor