Which one of the following statements is not correct ?

Options

A. Rhodospin is the purplish red protein present in rods only
B. Retina is the light absorbing portion of visual photo pigments
C. In retina the rods have the photo pigment rhodopsin while cones have three different photopigments.
D. Retina is a derivative of vitamin C

Explanation

To determine which statement is not correct, let's analyze each of the four statements provided:

1. **Statement 1**: "Rhodopsin is the purplish red protein present in rods only."
- **Analysis**: Rhodopsin is indeed a purplish-red protein found in the photoreceptor cells known as rods. It is crucial for vision in low light conditions. This statement is correct.

2. **Statement 2**: "Retinal is the light absorbing portion of visual photopigments."
- **Analysis**: Retinal is a derivative of vitamin A and is the light-absorbing part of visual photopigments. It is bound to proteins called opsins, which are responsible for the phototransduction process. This statement is also correct.

3. **Statement 3**: "In the retina, the rods have the photopigment Rhodopsin while cones have three different photopigments."
- **Analysis**: This statement is accurate as well. Rods contain Rhodopsin, while cones contain three different types of photopigments: Iodopsin, Porphyrosin, and Cyanopsin. This statement is correct.

4. **Statement 4**: "Retina is a derivative of vitamin C."
- **Analysis**: This statement is incorrect. The correct information is that retinal (not retina) is a derivative of vitamin A. The retina itself is the layer of tissue at the back of the eye that contains photoreceptor cells. Therefore, this statement is false.

Based on the analysis, the statement that is not correct is **Statement 4**.

### Final Answer:
The incorrect statement is: "Retina is a derivative of vitamin C."

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