Why is the inflow of sodium ions into a photoreceptor cell called "the dark current"?

a.) it causes photocells to stop working.
b.) it causes blindness.
c.) the inflow of ions occurs when the receptor is not receiving light.
d.) it only occurs with wavelengths outside of the visible spectrum.

The correct answer is: c.) The inflow of ions occurs when the receptor is not receiving light.

Activation of rods and cones (photoreceptor cells responsible for sight) is hyperpolarization which occurs when the light is present. In the dark, when they are not being stimulated, they depolarize and release glutamate continuously. In the dark, cells contain high concentration of cGMP, which opens sodium channels.

small, big, or no change could occur in the phenotype. it could cause something as simple as a cats ears to curl backwards or something as frighting as death. it could also occur in the protien-coding area and have an effect on that but no effect on the amino acids. what has to occur is a changing in the hox gene or the control gene.