Lab Report Digestive System

The function of the digestive system is to break down large food molecules, known as macromolecules, of carbohydrates, lipids and proteins into micro molecules that are small enough to be absorbed into the blood stream where the nutrients can be utilized by body cells. Food is not only broken down by chewing, which is a mechanical action, but by chemical action of digestive enzymes. Enzymes are large protein molecules produced by body cells. They are biological catalysts, which means they increase the rate of a chemical reaction without themselves becoming part of the product. As temperature increases, the rate of an enzyme-catalyzed reaction increases as well and works its best at around 37.5*C. However, very high temperatures denature enzymes

Their substrates, which are the molecules on which they act, are organic food molecules which they break down by adding water to the molecular bonds, which cleaves the bonds between the chemical building blocks, or monomers. In other words, a substrate is the structure with which an enzyme bonds with, to catalyze a reaction. Each enzyme in the digestive system works on a specific substrate, which in this experiment are carbohydrates, proteins or lipids. In the first experiment you will be investigating the hydrolysis of starch to maltose by salivary amylase. You must be able to identify the presence of starch and maltose, the breakdown product of starch, to determine to what extent the enzymatic activity has occurred. In the second experiment trypsin hydrolysis of BAPNA cleaves the dye molecule from the amino acid, causing the solution to change from no color to a bright yellow color. The color change is direct evidence of hydrolysis by trypsin. In the second experiment, fatty acids are organic acids that acidify solutions which decrease the PH. In order to recognize if digestion is ingoing or completed is to test the

Carbohydrate digestion begins in the mouth. The salivary glands release the enzyme salivary amylase, which begins to break down starches into simple sugars. Then three brush border enzymes in the small intestine break up the sugars lactose, maltose and sucrose into monosaccharides known as galactose, glucose and fructose. On to protein digestion which begins in the stomach, where HCl and pepsin break proteins into small subunits which then travel to the small intestine. The chemical digestion is continued through the small intestine by pancreatic enymes, including chymotrypsin and trypsin, each of which act on specific bonds in amino acid sequences. While at the same time, the cells of the Brush border secrete enzymes which results in amino acids small enough to enter the blood stream. Lastly, with fat digestion, which begins in the mouth with unemulsified triglycerides leads to the enzyme lingual lipase, then onto the stomach with the enzyme gastric lipase, then onto the small intestine where emulsification by te detergent action of bile salts ducted in from the liver, which leads to pancreatic lipases. Once this cycle is complete, the end result are monoglycerides and fatty