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Multiple Choice
Which of the following statements accurately describes vitamin A's role in vision?
A
Vitamin A directly absorbs light energy to initiate nerve impulses in the optic nerve.
B
Vitamin A is a precursor for retinal, a molecule essential for the formation of rhodopsin in the retina.
C
Vitamin A is only required for the maintenance of corneal structure and has no role in photoreception.
D
Vitamin A acts as an enzyme that converts glucose into ATP in photoreceptor cells.
Verified step by step guidance
1
Step 1: Understand the role of vitamin A in vision. Vitamin A is crucial for the synthesis of retinal, a molecule that combines with opsin proteins to form rhodopsin, a light-sensitive pigment in the retina.
Step 2: Clarify the function of rhodopsin. Rhodopsin is essential for photoreception, as it absorbs light and initiates a signal transduction pathway that leads to nerve impulses sent to the brain via the optic nerve.
Step 3: Eliminate incorrect statements. Vitamin A does not directly absorb light energy, nor does it act as an enzyme to convert glucose into ATP. Additionally, while vitamin A contributes to corneal health, its primary role in vision is related to photoreception through rhodopsin formation.
Step 4: Identify the correct statement. The accurate description is that vitamin A is a precursor for retinal, which is essential for rhodopsin formation in the retina.
Step 5: Summarize the importance of vitamin A in vision. Without sufficient vitamin A, the production of retinal and rhodopsin is impaired, leading to vision problems such as night blindness.