Which one of the following statemetns is not correct.

Options

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

Answer

To determine which statement is not correct, we will analyze each option provided in the question step by step.

### Step 1: Analyze the first statement
**Statement:** In the retina, rods have the photopigment rhodopsin while cones have three different photopigments.

**Analysis:** This statement is true. Rods contain rhodopsin, which is essential for vision in low light conditions. Cones, on the other hand, contain three types of photopigments: iodopsin, porphyrosin, and cyanopsin, which are responsible for color vision.

**Conclusion:** This statement is correct.

### Step 2: Analyze the second statement
**Statement:** Retinol is a derivative of vitamin C.

**Analysis:** This statement is false. Retinol is actually a derivative of vitamin A, not vitamin C.

**Conclusion:** This statement is incorrect.

### Step 3: Analyze the third statement
**Statement:** Rhodopsin is the purplish-red protein in rods only.

**Analysis:** This statement is true. Rhodopsin is indeed a purplish-red protein found exclusively in rod cells, and it plays a crucial role in night vision.

**Conclusion:** This statement is correct.

### Step 4: Analyze the fourth statement
**Statement:** Retinol is the light-absorbing portion of visual photopigments.

**Analysis:** This statement is true. Retinol, which is derived from vitamin A, is bound to opsins and is responsible for absorbing light, which is crucial for the visual process.

**Conclusion:** This statement is correct.

### Final Conclusion
After analyzing all the statements, the one that is not correct is: **Retinol is a derivative of vitamin C.**