Question

When light is absorbed by rod cells, which of the following events does not occur?

1) Retinal is converted from the 11-cis to the all-trans form.
2) The rod cells become depolarized.
3) The dark current of the rod cells is decreased.
4) The sodium channels close.

Answer 1

Rod cells hyperpolarize when light is absorbed; they do not depolarize, which is the event that does not occur.

Step-by-step explanation:

When light is absorbed by rod cells, several events occur, including retinal transitioning from the 11-cis to the all-trans form, which activates rhodopsin and initiates a cascade that closes sodium channels and decreases the dark current of the rods. This leads to hyperpolarization, not depolarization of the cell. So, the correct answer to the question, "When light is absorbed by rod cells, which of the following events does not occur?" is option 2) The rod cells become depolarized; instead, they become hyperpolarized.