Final answer:
Retinaldehyde or retinal is derived from carotenoids, specifically from the cleavage of beta-carotene in the liver. It's a crucial molecule in the process of vision, changing form upon photon interaction to enable sight.
Step-by-step explanation:
Retinaldehyde, also known as retinal, is derived from carotenoids, specifically beta-carotene. Retinal is involved in vision, functioning as a light-sensitive pigment within the eye. Beta-carotene is cleaved by the enzyme β-carotene 15, 15'-oxygenase in the liver, releasing two molecules of retinal. This process, which occurs in the presence of vitamin E, is essential for the conversion of light into electrochemical signals by the visual system. Retinal exists in two isomers - 11-cis-retinal before photon interaction, which is involved in vision, and all-trans-retinal after the photoisomerization reaction has taken place.