Lab Report, Fall 2011
East Tennessee State University
Department of Biological Sciences
By: Shelby Brackett
Date Performed: October 10, 2011
Lab Instructor: Joseph Kusi
Biology 1111, Section 018
Abstract
Enzymes are very important in chemical reactions. They are used to speed up the reaction taking place. They act by binding to a specific substrate and form an enzyme-substrate complex that may put stress on chemical bonds of that substrate. In this experiment, we used the amylase as our enzyme and starch as our specific substrate. We then used a calorimeter to measure the absorbance of our samples with the variable of pH over set periods of time. Our results indicated that at three different pH levels, the absorbance level of our samples was not the same for each one. This proved my original hypothesis to be incorrect, as I was surprised to find that the last pH buffer had no effect on the absorbance. The first two pH buffers supported my hypothesis, however. The levels of our samples kept decreasing over time. As with every experiment, it should be repeated several times to make sure your results are accurate.
Introduction
Most chemical reactions must be catalyzed (sped up) by protein molecules called enzymes. Enzymes are biological catalysts that facilitate specific chemical reactions. Enzymes are three-dimensional globular proteins that fit snugly around the molecules they act on. This fit facilitates chemical reactions by stressing particular chemical bonds. The three-dimensional shape enables it to stabilize a temporary association between substrates-the molecules that will undergo the reaction. The enzyme also lowers the activation energy required for new bonds to form. The reaction thus proceeds much more quickly than it would without the enzyme. (Mason, 2011). The energy of activation is the energy needed to get the substrate to its transition state. KI (potassium iodide)
Bibliography: Brady, Matt. What is Amylase? 2003. 22 October 2011 <http://www.wisegeek.com/what-is-amylase.htm>. Mason, Kenneth A., Jonathan B. Losos and Susan R. Singer. Biology. New York, NY: McGraw-Hill, 2011. The Effect of pH on Enzyme Activity. 2004. 22 October 2011 <http://academic.brooklyn.cuny.edu/biology/bio4fv/page/ph_and_.htm>.