Final answer:
When light hits a rod photoreceptor, it causes a shape change in retinal and activates rhodopsin, initiating a signaling cascade. This cascade results in the closing of sodium channels and hyperpolarization of the photoreceptor membrane. This amplifies the light signal and enhances the sensitivity of rod photoreceptors in low-light conditions.
Step-by-step explanation:
The light-induced signaling cascade in rod photoreceptors greatly amplifies the light signal through a series of events. When light hits a photoreceptor, it causes a shape change in the retinal molecule, which activates the rhodopsin protein. This activation triggers a cascade of enzymatic reactions, resulting in the closing of sodium channels and hyperpolarization of the photoreceptor membrane. This amplification process allows even a weak light signal to generate a strong neural signal, enhancing the sensitivity of rod photoreceptors in low-light conditions.