Which statement best describes the metabolism of the lens?

Which statement best describes the metabolism of the lens?

• A. Low metabolic activity with glucose anaerobic glycolysis metabolism via hexokinase pathway
• B. High metabolic activity with oxidative phosphorylation
• C. Metabolism via photosynthesis
• D. Metabolism uses amino acid catabolism as primary source

Answer: (A)

The lens keeps transparency by operating with low metabolic activity and relies on glucose being metabolized anaerobically through glycolysis. Because the lens is avascular and has few mitochondria, especially in the central fibers, its cells mainly use glycolysis to generate ATP. Glucose is phosphorylated by hexokinase to glucose-6-phosphate and enters the glycolytic pathway. In the low-oxygen environment of the lens, pyruvate is reduced to lactate rather than entering oxidative phosphorylation, providing just enough ATP to power essential ion pumps and maintain homeostasis. This explains why the statement describing low metabolic activity with glucose anaerobic glycolysis via the hexokinase step is the best fit. The other options don’t match the lens’s energy strategy: there isn’t high oxidative phosphorylation, the lens isn’t photosynthetic, and glucose—not amino acids—is the primary energy source.

The lens keeps transparency by operating with low metabolic activity and relies on glucose being metabolized anaerobically through glycolysis. Because the lens is avascular and has few mitochondria, especially in the central fibers, its cells mainly use glycolysis to generate ATP. Glucose is phosphorylated by hexokinase to glucose-6-phosphate and enters the glycolytic pathway. In the low-oxygen environment of the lens, pyruvate is reduced to lactate rather than entering oxidative phosphorylation, providing just enough ATP to power essential ion pumps and maintain homeostasis. This explains why the statement describing low metabolic activity with glucose anaerobic glycolysis via the hexokinase step is the best fit. The other options don’t match the lens’s energy strategy: there isn’t high oxidative phosphorylation, the lens isn’t photosynthetic, and glucose—not amino acids—is the primary energy source.