Vitamins and Coenzymes Questions and Answers

Answer: B

The match is P-(ii); Q-(iv); R-(v); S-(iii); T-(i).

• Copper (with haem iron) forms the redox centres of cytochrome oxidase (Complex IV).
• Selenium, as selenocysteine, is in the active site of glutathione peroxidase.
• Nickel is the metal of urease.
• Potassium ions are required for the activity of pyruvate kinase.
• Molybdenum is part of the iron-molybdenum cofactor of dinitrogenase.

The other options pair nickel or molybdenum with the wrong enzymes; for instance urease is the classic nickel enzyme, not a molybdenum one.

Answer: D

The correct match is P-4, Q-2, R-1, S-3.

• Vitamin B₁, thiamine, is active as thiamine pyrophosphate.
• Vitamin B₂, riboflavin, forms flavin mononucleotide (FMN) and FAD.
• Vitamin B₅, pantothenic acid, is part of coenzyme A.
• Vitamin B₆, pyridoxine, is active as pyridoxal phosphate.

P-4, Q-3, R-2, S-1 gets thiamine right but mismatches the other three. P-1, Q-2, R-3, S-4 simply pairs the lists in printed order.

Answer: B

Coenzyme A is derived from pantothenic acid (vitamin B5).

Coenzyme A is built from pantothenic acid, cysteamine (from cysteine) and a 3'-phosphorylated ADP. Its terminal thiol forms thioesters such as acetyl-CoA, which carry acyl groups in the citric acid cycle and in fatty acid synthesis and oxidation.

The other vitamins make different coenzymes: riboflavin (B2) gives FAD and FMN, folic acid gives tetrahydrofolate for one-carbon transfers, and pyridoxine (B6) gives pyridoxal phosphate for amino acid metabolism.

Answer: B

The correct match is (i) - (p), (ii) - (r), (iii) - (q), (iv) - (s), (v) - (t).

• Vitamin A: night blindness, since it forms retinal for the rod pigment rhodopsin.
• Vitamin D: bone softening, as rickets in children and osteomalacia in adults, from poor calcium absorption.
• Vitamin B6: anaemia, because pyridoxal phosphate is needed for the first step of haem synthesis.
• Vitamin C: delayed wound healing, as in scurvy, because it is needed to make stable collagen.
• Vitamin K: prolonged bleeding, because it is needed to activate clotting factors II, VII, IX and X.

The other options pair vitamin D with anaemia, or swap the symptoms of vitamins C and K, or give vitamin A anaemia; each breaks at least one of these pairs.

Answer: A

Riboflavin deficiency causes Cheilosis.

Riboflavin is vitamin B₂. Its deficiency causes cheilosis (fissuring at the corners of the mouth and lips), along with digestive disorders and a burning sensation of the skin.

The others belong to different vitamins: rickets to vitamin D, beri beri to thiamine (B₁), scurvy to vitamin C, and xerophthalmia to vitamin A.

Answer: D

The deficiency that causes convulsions is that of Pyridoxine (vitamin B₆).

Pyridoxine is needed to make several neurotransmitters, and a lack of it can lead to convulsions, especially in infants. This is the deficiency disease listed for vitamin B₆ in the standard table of vitamins.

The others are matched with different conditions: riboflavin (B₂) with cheilosis and cracking at the corners of the mouth, thiamine (B₁) with beriberi, ascorbic acid (vitamin C) with scurvy and bleeding gums, and vitamin D with rickets in children and osteomalacia in adults.

Answer: E

The correct match is (a)-(iii), (b)-(iv), (c)-(ii), (d)-(i).

• Vitamin A: fish liver oil, a classic rich source (with carrots, butter and milk).
• Vitamin B₁ (thiamine): yeast, with milk, green vegetables and cereals.
• Vitamin C: amla, the Indian gooseberry, among citrus fruits and green leafy vegetables.
• Vitamin E: vegetable oils such as sunflower oil and wheat germ oil.

Every option has (a)-(iii), so the question turns on the other three. The options giving B₁ amla or sunflower oil, or vitamin C sunflower oil or yeast, mismatch these standard sources.

Answer: D

The vitamin is ascorbic acid, vitamin C.

Ascorbic acid is the water-soluble vitamin found in citrus fruits, amla and green leafy vegetables. Its deficiency causes scurvy, and since it is not stored in the body it must be taken in the diet regularly.

Aspartic acid, glutamic acid and valine are amino acids, building blocks of proteins, not vitamins. Saccharic acid (glucaric acid) is the dicarboxylic acid formed when glucose is oxidised by nitric acid.

Answer: B

The vitamin is vitamin-E.

Vitamin E (tocopherols) is fat-soluble and occurs in vegetable oils such as wheat germ and sunflower oil. In the NCERT summary of vitamins, its deficiency is associated with increased fragility of red blood cells and muscular weakness.

Vitamin A deficiency causes night blindness and xerophthalmia, vitamin D deficiency causes rickets, vitamin B6 deficiency causes convulsions, and vitamin B12 deficiency causes pernicious anaemia.