5. Describe the process of digestion of protein in the stomach.
Answer
Stomach is the first organ where the digestion of proteins starts while the small intestine is the part where protein digestion ends. The stomach possesses gastric glands which secrete gastric juices containing enzymes that act on food. Gastric juice mainly contains hydrochloric acid, pepsinogen, mucus, and renin. Firstly, the food that enters the stomach becomes acidic when it mixes with the gastric juice. The function of these components in protein digestion is as follows:
1. Hydrochloric acid dissolves the food particle and creates an acidic medium inside the stomach. Acidic medium is a pre-requisite for the conversion of inactive enzyme pepsinogen into active pepsin.
2. Pepsin is a protein-digesting enzyme that converts proteins into proteases and peptides.
3. Rennin which plays an important part in the coagulation of milk is a proteolytic enzyme which is released as prorennin i.e. inactive rennin.