Which one of the following statements is not correct?
- Retinal is the light absorbing portion of visual photo pigments.
- In retina the rods have the photopigment rhodopsin while cones have three different photopigments.
- Retinal is a derivative of vitamin C.
- Rhodopsin is the purplish red protein present in rods only.
Answer
(3) Retinal is a derivative of vitamin C.
Solution
As per NCERT, the photopigments are composed of opsin (a protein) and retinal (an aldehyde of vitamin A).
Retinal is the light-absorbing part of the photopigment, so statement (1) is correct. Rods contain rhodopsin (visual purple) and cones contain three types of photopigments (for red, green and blue light), so statements (2) and (4) are also correct.
∴ Retinal is a derivative of vitamin A, not vitamin C; statement (3) is not correct.
Answer: (3)