Vitamins (Functions)

Question 1

Vitamin A

Answer 1

Retinol, ß-Carotene

• Visual pigments in the retina
• Regulation of gene expression & cell differentiation
• (ß-Carotene is an antioxidant)

Question 2

Vitamin D

Answer 2

Calciferol

• Maintenance of calcium balance
• Enhances intestinal absorption of Ca²⁺ & mobilizes bone mineral
• Regulation of gene expression & cell differentiation

Question 3

Vitamin E

Answer 3

Tocopherols, Tocotrienols

• Antioxidant, especially in cell membranes
• Roles in cell signaling

Question 4

Vitamin K

Answer 4

Phylloquinone, Menaquinones

• Coenzyme in formation of γ-carboxyglutamate in enzymes of blood clotting & bone matrix

Question 5

Vitamin B₁

Answer 5

Thiamin

• Coenzyme in pyruvate & α-ketoglutarate dehydrogenases, & transketolase
• Regulates Cl^- channel in nerve conduction

Question 6

Vitamin B₂

Answer 6

Riboflavin

• Coenzyme in oxidation & reduction reactions (FAD & FMN)
• Prosthetic group of flavoproteins

Question 7

Vitamin B₃

Answer 7

Niacin, Nicotinic Acid, Nicotinamide

• Coenzyme in oxidation & reduction reactions
• Functional part of NAD & NADP
• Role in intracellular calcium regulation & cell signaling

Question 8

Vitamin B₆

Answer 8

Pyridoxine, Pyridoxal, Pyridoxamine

• Coenzyme in transamination & decarboxylation of amino acids & glycogen phosphyorylase
• Modulation of steriod hormone action

Question 9

Vitamin B₉

Answer 9

Folic Acid

• Coenzyme in transfer of one-carbon fragments

Question 10

Vitamin B₁₂

Answer 10

Cobalamin

• Coenzyme in transfer of one-carbon fragments & metabolism of folic acid

Question 11

Vitamin B₅

Answer 11

Pantothenic Acid

• Functional part of CoA & acyl carrier protein
• Fatty acid synthesis & metabolism

Question 12

Vitamin H

Answer 12

Biotin

• Coenzyme in carboxylation reactions in gluconeogenesis & fatty acid synthesis
• Role in regulation of cell cycle

Question 13

Vitamin C

Answer 13

Ascorbic Acid

• Coenzyme in hydroxylation of proline & lysine in collagen synthesis
• Antioxidant
• Enhances absorption of iron