Question

Which one of the following is the correct difference between rod cells and cone cells of our retina ?

• A. Overall function Vision in poor light Colour vision and detailed vision in bright light
• B. Distribution More concentrated in centre of retina Evenly distributed all over retina
• C. Visual activity high low
• D. Visual pigment contained lodopsin Rhodopsin

Answer 1

The Correct Option is A

The question asks about the differences between rod cells and cone cells in the retina. To provide a comprehensive answer, let's understand the functions of both types of cells, as well as their distribution and visual capabilities:

1. Functions:
   • Rod Cells: They are primarily responsible for vision in low-light conditions. Rod cells are more sensitive to light than cone cells and do not mediate color vision. Therefore, they provide night vision.
   • Cone Cells: These cells are responsible for color vision and are active at higher light levels. They enable detailed vision which is important in bright light environments.

   Thus, the correct difference in terms of their function is: Vision in poor light for rods and Colour vision and detailed vision in bright light for cones.

2. Distribution:
   • Rod Cells: They are more concentrated at the periphery of the retina and are absent from the fovea (the center of the retina).
   • Cone Cells: These are concentrated in the center of the retina, particularly at the fovea, where most detailed and color vision occurs.

   Therefore, stating that cones are "Evenly distributed all over retina" is incorrect; they are concentrated in the center.

3. Visual Activity:
   • Rod Cells: These have low visual acuity or sharpness because they do not discern colors.
   • Cone Cells: They have high visual acuity and are responsible for detailed vision.

   This makes the statement "Visual activity high low" an incorrect description, as it should describe rods instead of cones.

4. Visual Pigment:
   • Rod Cells: Contain the visual pigment rhodopsin, which is very sensitive to light.
   • Cone Cells: Contain different types of opsins for detecting different colors (iodopsin), but not rhodopsin.

   The statement "Visual pigment contained lodopsin Rhodopsin" is incorrect because "lodopsin" refers to the types of pigments in cones but is not more precise than the actual function description.

Conclusively, the most accurate option about their main difference is the functional one, which describes the rods' role in low-light vision and the cones' role in color and detailed vision:

Correct Answer: Overall function - Vision in poor light (rod cells) and Colour vision and detailed vision in bright light (cone cells)