Final answer:
The dissociation of retinal from opsin after light absorption is due to photoisomerization of retinal, resulting in the release of opsin, leading to visual signal transduction.
Step-by-step explanation:
When rhodopsin absorbs light, the dissociation of retinal from opsin is due to photoisomerization of retinal, causing opsin to dissociate from the membranous discs. The correct answer is 1) retinal, opsin.
Upon the absorption of light, the retinal undergoes a change in shape from a cis to a trans form. This process triggers the dissociation of opsin and initiates a sequence of reactions involving the activation of the G-protein named transducin, further leading to the hyperpolarization of the photoreceptor cell and the subsequent neural signaling necessary for vision.