composition structure and function of fat soluble vitamins

                                                          VITAMIN

Funk introduced vitamin as vitamin's are can be defined as natural organic substance which are required in very low amount to be healthy and they are to be supplied by food if they not synthesized by organs.
except- vitamin D
*Vitamins are complex organic compounds.
*In plants many protein synthesized comparing to animals.
*Human body need 15 vitamin compulsorily. 
*Vitamin works like hormones.
*Vitamin doesn't gives energy but it control all metabolic activities.
*On high temperature Vitamins are destroyed.
It is also called as accessory food substances. Vitamin's are divided in two groups-
                1.FAT SOLUBLE VITAMINS-

        Vitamin A,D,E and K are fat soluble vitamins.

                                    (a)VITAMIN A
                            It is first fat soluble vitamin discovered by Mc. collum and Davis. the other name of this vitamin is "Anti infection vitamin". Its a complex primary alcohol.

Vitamin A is found in two form's. which are-Renitol 1 and Renitol 2.
Beta carotene is the precursor of vitamin A because its formed by oxidative splitting of beta carotene.

Read about nucleic acid here-
structure and function of nucleic acid

SOURCES- sources of vitamin A are egg yolk, fish oil, milk, cheese, tomato, papaya and yellow vegetable. It also formed on our body from certain carotenes. Vitamin A synthesized in liver.

FUNCTIONS-

1. Vitamin A is very important for rhodopsin of rod cells and idopsin of cone cells of the retina of eye.

2. Required for normal growth of tear gland.

3. Vitamin A makes the skin healthy and soft.

4. It is antioxidant.

DEFICIENCY SYMPTOMS-

1. Nyctalopia( Night blindness)

2. Xerophthalmia (Drying of eyeball because tears are not produced.

3. Dermatosis (dry and scaly skin)

4. Retarded growth of body.
                                         (b)Vitamin D

Chemical name- Cholecalciferol/ Ergocalciferol
mc collum discover this vitamin in 1922. its nature is like steroid.
It present in nature in 5 forms-D1,D2,D3,D4 and D5. vitamin D2 find commonly. Vitamin D is synthesized by Ergosterol in presence of sun light. In human body cholesterol present in skin which converts in vitamin D in sun light. it is called as Antirachitic vitamin or Sunshine vitamin also.
SOURCE- fish oil, butter, milk , egg.

Functions-
1.It regulates calcium and phosphorus metabolism.
2. Important for normal growth of teeth and bones.

DEFICIENCY SYMPTOMS-
Rickets in children( softness of bone like bow-legs and pigeon chests)
Osteomalacia in adults(weak bone liable to easy fracture)


                                     VITAMIN E

Chemical name-Tocopherol
other name- Anti-sterility vitamin 
Vitamin E is a mixture of several related compounds. Several different tochopherols having vitamin E activity have been found in plants the most active is alpha tochopherol. It has a chromone ring system  which caontain four metyl groups,one phenolic group and a phytyl side chain.

Source-Egg yolk,wheat,milk, butter,leafy vegetables,vegetable oil.

Daily requirement-20 mg

Functions- this vitamin play primary role to serve as an antioxidant of certain materials. Vitamin E maintain erythrocytes and keep the skins wellness.To curing cancer tumour its useful.vitamin E is important for reproduction and muscles.

Deficiency symptoms-
*Reproductive failure
*Degeneration of muscles
*Haemolysis of erythrocytes which calls anaemia

                                  Vitamin K

this vitamin is discovered by Dam in 1935.

Biological target-Gamma qlutamyl carboxylase

 Vitamin K is group of two compounds- vitamin K1 and vitamin K2
Function-Is is helpful in prothombin's synthesis. So it also calls antihimoregic vitamin.
Source-this vitamin is synthesized by green plants and micro-bacteria. mostly it taken from tomato,soya-bin,milk,fat and egg.
Vitamin K take part in phosphorylation of oxidative elements.

Deficiency- If a human has deficiency of this vitamin and injured then blood doesn't clots. 
click here for  read other vitamins-

WATER SOLUBLE VITAMIN