Hint: The digestion of food takes place in the alimentary canal. It starts from the oral cavity or mouth and ends in anus. Every part of the GI tract produces digestive enzymes which help in breakdown of food into simpler substances which can be easily utilized by our body.
To solve this question, we must know about the movement of food in the different parts of the GI tract.
The food we eat is injected through our mouth and the waste is eliminated from our body through mouth. The pathway of food is as follows.
1.Mouth- The food we eat is ingested through the mouth. The digestive enzyme in our mouth i.e. salivary amylase helps in breaking the starch present in our food.
2.Stomach- It is an important part of the GI tract. The stomach produces HCL and pepsin which helps in digestion of protein. The other enzymes present are trypsin and chymotrypsin secreted by the pancreas into the stomach which helps in breaking down proteins. The fat is emulsified by the enzyme called gastric lipase.
3.Small intestine produces digestive enzymes like lactase, maltase, and sucrose, erepsin which further helps in breakdown of milk, maltose, sucrose and nucleotides.
Note: The enzymes are secreted by the exocrine glands. The salivary gland present in the mouth, the gastric gland in stomach, the secretary cells in the pancreas and the secretary glands present in the intestine produce the digestive enzymes which act on the target substrate lysis.