PG NEXT Question of the Day 02-11-2016
The food item shown below is a rich source of
a. Vitamin C
b. Vitamin A
c. Vitamin D
d. Vitamin K
Answer : a) Vitamin C
DM Vasudevan , Textbook of biochemistry for medical students , 7th ed , page 496
It is water soluble and is easily destroyed by heat, alkali and storage. In the process of cooking, 70% of vitamin C is lost.Most animals and plants can synthesize ascorbic acid from glucose. Man, higher primates, guinea pigs and bats are the only species which cannot synthesize ascorbic acid (block in gulonolactone oxidase step). They lack the genes responsible for the synthesis of this enzyme.
Biochemical functions of vitamin C include reversible oxidation reduction , hydroxylation of proline and lysine , metabolism of Tryptophan , tyrosine , iron ,haemoglobin and folic acid , Steroid syntehesis , Phagocytosis and antioxidant property.
Manifestations of Vitamin C Deficiency : Scurvy , Barlows Disease , Hemorrhagic Tendency , Internal Hemorrhage , gum bleeding , bone fractures and Anemia.
Rich sources are amla (Indian gooseberry) (700 mg/100 g),guava (300 mg/100 g), lime, lemon and green leafy vegetables