Question

Signal transduction- what structure of the eye converts photons of light to an action potential?

Answer 1

Rods and cones in the retina convert light photons into action potentials using the photopigment rhodopsin. The process involves the conversion of retinal from cis to trans, the activation of the G-protein transducin, and a cascading effect that results in hyperpolarization and neurotransmitter release modulation.

Step-by-step explanation:

The structure of the eye that converts photons of light to an action potential is the retina, specifically the photoreceptors known as rods and cones. These photoreceptors contain the photopigment rhodopsin, which is composed of a membrane protein called opsin and a molecule called retinal. When photons strike rhodopsin, retinal undergoes a change in shape from cis to trans form, activating a G-protein called transducin, which leads to a series of biochemical events culminating in the hyperpolarization of the photoreceptor cell and the eventual generation of action potentials in the retinal ganglion cells. These events include the closure of sodium channels as cGMP is converted to GMP by phosphodiesterase. The hyperpolarization reduces the release of the neurotransmitter glutamate to bipolar cells. Subsequently, the retinal ganglion cells (RGCs) translate these signals into action potentials, which travel along the optic nerve to the brain where they are interpreted as visual information.

Answer 2

What structure of the eye converts photons of light to an action potential?-Depolarized bipolar cells fire an action potential that releases neurotransmitter onto the ganglion cells, which fire an action potential that goes down the optic nerve to the brain. Important parts of eye: cornea, aqueous humor, iris, pupil, lens, vitreous humor, retina.