Transport of Ascorbic acid to the lens is done by –
**Core Concept**
Ascorbic acid transport to the lens is a crucial aspect of maintaining the lens's transparency and refractive function. The transport of ascorbic acid is facilitated by a specific mechanism that involves the interaction of various proteins and cellular components.
**Why the Correct Answer is Right**
Ascorbic acid is transported to the lens through a sodium-dependent mechanism, involving the sodium-ascorbate cotransporter (SVCT2). This transporter is responsible for the uptake of ascorbic acid into the lens epithelial cells, which is essential for maintaining the lens's transparency and preventing cataract formation. The sodium gradient across the cell membrane drives the transport of ascorbic acid into the cells, where it is then reduced to dehydroascorbic acid and further broken down to ascorbic acid.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not accurately describe the primary mechanism of ascorbic acid transport to the lens.
* **Option B:** This option is incorrect because it is not specific to the lens and does not accurately describe the transport mechanism.
* **Option D:** This option is incorrect because it is not relevant to the transport of ascorbic acid to the lens.
**Clinical Pearl / High-Yield Fact**
The sodium-ascorbate cotransporter (SVCT2) is a high-affinity transporter that is responsible for the uptake of ascorbic acid into the lens epithelial cells. This transporter is essential for maintaining the lens's transparency and preventing cataract formation.
**Correct Answer: C. Sodium-dependent mechanism.**