Question

Mention the role of following in digestion: (i) pepsin (ii) saliva (iii) villi.

Answer 1

Digestion:

1. Human beings are omnivorous.
2. They feed on different parts of the plants like roots, shoots, fruits, and seeds.
3. They also consume animal products like eggs, meat, and milk.
4. The food we eat is broken down into simpler molecules in the digestive system.
5. The process by which your body breaks down food into small nutrient molecules is called digestion.
6. Digestion of food involves both physical and chemical changes.
7. The role of the following in the digestion are:-

(i) Pepsin:

1. It is secreted in an inactive form, pepsinogen.
2. In presence of HCl, it is converted into the active form pepsin.
3. It hydrolyses the protein molecules into proteases and peptones.

(ii) Saliva:

1. Saliva is released by salivary glands in the mouth.
2. It helps in the digestion of starch.

(iii) Villi:

1. Villi are finger-like projections in the small intestine.
2. It helps in providing extra surface area for the absorption of water and minerals in the intestine.