Biochemistry Vitamins Essay Questions And Answers

Vitamins

Classify vitamins. Indicate dietary sources, daily requirements & deficiency of fat-soluble vitamins, Briefly explain the role of vitamin A In the vision (or) Give the sources, functions & deficiency symptoms of vitamin A. (or) Vitamin A deficiency.
Answer:

Vitamins:

Classification:

• Vitamins are classified into

Read And Learn More: BDS Previous Examination Question And Answers

1. Fat Soluble Vitamins
   • Vitamin A
   • Vitamin D
   • Vitamin E
   • Vitamin k
2. Water-soluble vitamins
   1. Vitamin B
      • Energy releasing vitamins
      • B1- Thiamine
      • B2- Riboflavin
      • B3- Niacin
      • B6- Pyridoxine
      • 7- Biotin
      • Pantothenic acid
   2. Hemopoietic vitamins
      • B12- Cyanocobalamin
      • Folic acid

Fat Soluble Vitamins:

1. Role of vitamin A in vision:
   • Retinol and retinal k retinoic acid are forms of vitamin A
   • Retinal takes part in a visual cycle called Rhodopsin Cycle or Wald’s visual cycle
   • In this cycle, initially on exposure to light isomer/atum of 11 I is-retinal to aII Irate, retinal occurs
   • All trans-retinal is immediately isomer/ed to 11 cis-retinal
   • This combines with opsin k forms Rhodopsin
   • Most of the all-trans-retinal is the transporter to liver
   • It is converted to all trans-retinol by alcohol dehydrogenase
   • All trans-retinol is isomerized to 11-cis-retinol
   • This is oxidized to 11-cis-retinal by alcohol dehydrogenase
   • Now this re-enters into the visual cycle