The body uses the vitamin A precursors from some foods to make a substance called retinal, which __________.

• A. provides energy for the function of rods and cones
• B. colors the iris of the eye
• C. stimulates the neurons in the retina to form branches and connections
• D. keeps the lens clear and transparent
• E. is a visual pigment that absorbs light

Answer: (E)

Verified step by step guidance

1. Understand the role of vitamin A in the body: Vitamin A is essential for vision, immune function, and skin health. It is obtained from dietary sources either directly as vitamin A or as precursors like beta-carotene, which the body converts into vitamin A.
2. Learn about retinal: Retinal is a form of vitamin A that is crucial for vision. It is a component of the visual pigment rhodopsin, found in the photoreceptor cells of the retina.
3. Explore the function of rhodopsin: Rhodopsin is a light-sensitive receptor protein involved in visual phototransduction. It is located in the rods of the retina and is responsible for the perception of light.
4. Understand the process of light absorption: When light hits the retina, retinal changes shape, initiating a signal transduction pathway that ultimately results in the perception of light. This process is essential for vision, particularly in low-light conditions.
5. Clarify the role of retinal in vision: Retinal is not directly involved in providing energy, coloring the iris, stimulating neurons, or keeping the lens clear. Its primary function is to absorb light as part of the visual pigment, enabling the conversion of light into visual signals.