Question

Name the enzymes involved in the digestion of starch, protein, and fat, and tell where these enzymes are active and what they do. (page 165 )

Short answer

The enzymes involved in the digestion of starch, protein, and fat are: 1. Starch: Amylase (in the mouth and small intestine) breaks starch into maltose, and maltase (in the small intestine) breaks maltose into glucose. 2. Protein: Pepsin (in the stomach) breaks proteins into smaller polypeptides, trypsin (in the small intestine) breaks polypeptides into smaller peptides, and peptidase (in the small intestine) breaks peptides into amino acids. 3. Fat: Lipase (in the small intestine) breaks fats into fatty acids and glycerol, with bile aiding in emulsification.

Step-by-step solution

Enzymes involved in the digestion of starch

Starch is a complex carbohydrate that needs to be broken down into simpler sugars to be absorbed by our bodies. The enzymes involved in the digestion of starch are amylase and maltase. - Amylase: This enzyme is produced in the salivary glands and the pancreas. In the mouth, salivary amylase initiates the breakdown of starch into maltose (a disaccharide), and in the small intestine, pancreatic amylase continues this process. - Maltase: This enzyme is produced by the cells lining the small intestine. Maltase acts on maltose and breaks it down into two glucose molecules, which can then be absorbed by the body.

Enzymes involved in the digestion of proteins

Proteins are made up of chains of amino acids and need to be broken down into individual amino acids to be absorbed by the body. The enzymes involved in the digestion of proteins are pepsin, trypsin, and peptidase. - Pepsin: Pepsin is produced in the stomach by chief cells as the inactive enzyme pepsinogen. The acidic environment of the stomach activates pepsinogen into pepsin, which begins the process of breaking down protein into smaller polypeptides. - Trypsin: Trypsin is produced in the pancreas as the inactive enzyme trypsinogen and is secreted into the small intestine. Enterokinase, an enzyme produced by the cells lining the small intestine, activates trypsinogen into trypsin. Trypsin then breaks down the smaller polypeptides into even smaller peptides. - Peptidase: Peptidases are produced by the cells lining the small intestine. They complete the digestion of proteins by breaking down the small peptides into individual amino acids, which can then be absorbed by the body.

Enzymes involved in the digestion of fats

Fats are large molecules that need to be broken down into fatty acids and glycerol to be absorbed by the body. The primary enzyme involved in the digestion of fats is lipase. - Lipase: Lipase is produced in the pancreas and secreted into the small intestine. It breaks down the fats into their constituent fatty acids and glycerol. Bile, produced in the liver and stored in the gallbladder, is also secreted into the small intestine to help emulsify the fats, creating a larger surface area for lipase to work on. In conclusion, the enzymes involved in the digestion of starch, protein, and fat are amylase and maltase for starch, pepsin, trypsin, and peptidase for protein, and lipase for fat. These enzymes are active in different parts of the digestive system and are responsible for breaking down their respective macromolecules into simpler forms that can be absorbed by our bodies.