Vitamins are organic compounds required in the diet in small amounts to perform specific biological functions for normal maintenance of optimum growth and health of the organism. Their deficiency causes specific diseases. Most of the vitamins cannot be synthesised in our body, but plants can synthesise almost all of them.
Vitamins are classified into two groups depending upon their solubility in water or fat. Vitamins which are soluble in fat and oils but insoluble in water are called fat soluble vitamins. These are vitamins A, D, E and K. They are stored in liver and adipose (fat storing) tissues. B group vitamins and vitamin C are soluble in water and are called water soluble vitamins. Water soluble vitamins must be supplied regularly in the diet because they are readily excreted in urine and cannot be stored (except vitamin B12) in our body.
Chemically, the digestion of food is a process of:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Hydrolysis
Food contains large molecules such as starch, disaccharides and proteins. Digestion breaks them into small units (such as glucose and amino acids) by reaction with water at the linkages that hold the units together.
Breaking a bond by reaction with water is hydrolysis; in the body each step is catalysed by an enzyme. For example, maltase hydrolyses maltose to glucose:
\( \displaystyle \ce{C12H22O11 + H2O} \xrightarrow{\text{maltase}} \ce{2C6H12O6} \)
Why the other options are incorrect
Option (1) Hydrogenation — Incorrect. Hydrogenation is the addition of hydrogen to a molecule; digestion adds water, not hydrogen.
Option (3) Anabolism — Incorrect. Anabolism builds up large molecules from small ones, the opposite of what digestion does.
Option (4) Dehydrogenation — Incorrect. Dehydrogenation removes hydrogen (an oxidation); it does not split food molecules into their units.
NCERT (2026-27 edition):
10.3 Enzymes – “Life is possible due to the coordination of various chemical reactions in living organisms. An example is the digestion of food, absorption of appropriate molecules and ultimately production of energy. … For example, the enzyme that catalyses hydrolysis of maltose into glucose is named as maltase.”
10.1.3 Disaccharides – “You have already read that disaccharides on hydrolysis with dilute acids or enzymes yield two molecules of either the same or different monosaccharides.”