In the absence of light, the membrane potential of a photoreceptor is relatively _________by the presence of open __________ channels.
A) depolarized : potassium
B) hyperpolarized : potassium
C) hyperpolarized : sodium
D) depolarized : calcium
E) depolarized : sodium

Question

Quizplus · Accepted Answer

In the absence of light, photoreceptors are relatively depolarized due to the presence of open sodium channels. This depolarization is part of the dark current, where the influx of sodium ions into the cell keeps it in a depolarized state.

In the Absence of Light, the Membrane Potential of a Photoreceptor