Which vitamin deficiency causes night blindness (nyctalopia) and can progress to severe corneal xerophthalmia?
Answer and explanation
Correct answer: A. Vitamin A
- Step 1: Vitamin A (retinol) is an essential precursor for rhodopsin, the light-sensitive photopigment in retinal rod cells. Step 2. Deficiency impairs low-light rod vision and causes keratinization of conjunctival epithelium. Answer: Vitamin A. Why not the others: Vitamin C deficiency causes scurvy; Vitamin D deficiency causes rickets; Vitamin K deficiency impairs prothrombin synthesis.
Practise more Biological Sciences, Genetics and Physiology.
Free questions with an explanation for every one, and full timed Bangladesh Civil Service Preliminary Examination mock tests.
More Biological Sciences, Genetics and Physiology questions
- Which cellular organelle is known as the powerhouse of the cell because it synthesizes the majority of adenosine triphosphate (ATP)?
- Which cellular structures are the primary sites of biological protein synthesis in both prokaryotic and eukaryotic cells?
- During the light-dependent reactions of oxygenic photosynthesis in green plants, where does the photolysis of water molecules occur?
- Which key photosynthetic enzyme catalyzes the fixation of carbon dioxide to ribulose-1,5-bisphosphate in the Calvin cycle?
- Which complex vascular plant tissue is responsible for transporting water and dissolved inorganic minerals upward from roots to leaves?
- Which plant hormone is synthesized in shoot apical meristems and induces phototropic bending by stimulating cell elongation on the shaded si…