Digestion of Starch by the Action of Salivary Amylase
Austin Peay State University Department of Chemistry
CHEM 1021
BREAKING DOWN STARCH USING SALIVARY AMYLASE Caution: You will be using a Bunsen burner and glassware to create your own constant water bath. Appropriate caution should be exercised when dealing with the Bunsen burner, hot water, and glassware. Purpose: Many plants store their energy in the form of starch, a polysaccharide made from repeating units of the monosaccharide glucose. Our bodies break down starch into the individual glucose units, which are further metabolized into CO2 and water through the process of glycolysis—this is the process we commonly call digestion. The enzyme amylase is present in our saliva and begins the process of digestion when starch containing foods enter our mouths. In this lab you will measure the amount of amylase present in your saliva by monitoring the breakdown of starch. Introduction: You can probably name a variety of foods that are referred to as “starchy”. Such foods include potatoes, rice, wheat, and corn. In essence, the starch is a long biopolymer made from thousands of repeating glucose units. When these glucose units are attached in a straight line, the type of starch is called amylose. When the units are branched, the type of starch is called amylopectin. Natural starch contains both forms of the polymer (Figure 1). The long chains of glucose that make amylose form a tight helix. If we mix an iodine solution with the amylose, the iodine will lodge itself in the interior of the helix. This causes the solution to turn a dark blue color. If the enzyme amylase is added to the solution first, it will chemically remove one glucose monomer at a time from the ends. Addition of iodine to this solution does not give a blue color but will be colorless (Distinguish between clear and colorless;
CHEM 1021
BREAKING DOWN STARCH USING SALIVARY AMYLASE Caution: You will be using a Bunsen burner and glassware to create your own constant water bath. Appropriate caution should be exercised when dealing with the Bunsen burner, hot water, and glassware. Purpose: Many plants store their energy in the form of starch, a polysaccharide made from repeating units of the monosaccharide glucose. Our bodies break down starch into the individual glucose units, which are further metabolized into CO2 and water through the process of glycolysis—this is the process we commonly call digestion. The enzyme amylase is present in our saliva and begins the process of digestion when starch containing foods enter our mouths. In this lab you will measure the amount of amylase present in your saliva by monitoring the breakdown of starch. Introduction: You can probably name a variety of foods that are referred to as “starchy”. Such foods include potatoes, rice, wheat, and corn. In essence, the starch is a long biopolymer made from thousands of repeating glucose units. When these glucose units are attached in a straight line, the type of starch is called amylose. When the units are branched, the type of starch is called amylopectin. Natural starch contains both forms of the polymer (Figure 1). The long chains of glucose that make amylose form a tight helix. If we mix an iodine solution with the amylose, the iodine will lodge itself in the interior of the helix. This causes the solution to turn a dark blue color. If the enzyme amylase is added to the solution first, it will chemically remove one glucose monomer at a time from the ends. Addition of iodine to this solution does not give a blue color but will be colorless (Distinguish between clear and colorless;