Consider statements about vitamins: 1. Vitamin A is essential for good vision. 2. Vitamin C prevents scurvy. 3. Vitamin D is essential for blood clotting. Which are correct? MCQ with Answer and Explanation
Consider statements about vitamins: 1. Vitamin A is essential for good vision. 2. Vitamin C prevents scurvy. 3. Vitamin D is essential for blood clotting. Which are correct?
A. 1 and 3 only
B. 1 and 2 only
C. 2 and 3 only
D. 1, 2 and 3
Answer: Option B
Solution (By JKExamLibrary)
Vitamin A (retinol) is crucial for the maintenance of the cornea and the synthesis of rhodopsin, a pigment necessary for vision in dim light. Vitamin C (ascorbic acid) is essential for the synthesis of collagen; its deficiency leads to scurvy, characterized by bleeding gums and poor wound healing. Vitamin K, not Vitamin D, is essential for the synthesis of prothrombin and other clotting factors. Vitamin D is essential for calcium absorption and bone health. Thus, statements 1 and 2 are correct.
Explanation:
A food chain shows the flow of energy from producer to consumers. Grass (producer) → Grasshopper (primary consumer/herbivore) → Frog (secondary consumer/carnivore) → Snake (tertiary consumer). Arrows point in the direction of energy flow. Option A has incorrect order, C and D start with consumer. Typically, energy decreases at each trophic level. This illustrates the correct trophic sequence.
Explanation:
Streptomycin is an antibiotic produced by the bacterium Streptomyces griseus. Penicillin and cephalosporins are from fungi (Penicillium and Cephalosporium). Griseofulvin is a fungal antibiotic. Streptomycin is a broad-spectrum aminoglycoside, effective against gram-negative bacteria and Mycobacterium tuberculosis. It inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit.
Explanation:
Phenylketonuria (PKU) is an autosomal recessive disorder due to deficiency of phenylalanine hydroxylase, leading to accumulation of phenylalanine, causing mental retardation if untreated. Albinism is tyrosinase deficiency, sickle cell HbS mutation, cystic fibrosis CFTR defect.
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