I. Introduction/Background/Purpose/Hypothesis Essays - Catalysis

I. Introduction/Background/Purpose/Hypothesis: BACKROUND: An enzyme is a protein that controls the chemical reactions that take place in the body. Enzymes help by catalyzing (speeding up) the reaction and intern lowering the activation energy required for the reaction to occur. Molecules called substrates bind with enzymes during reactions. However each enzyme has a very specific purpose. The shape of the active site on the enzyme's outer layer determines that purpose, along with deciding which substrates can bind with that specific enzyme. The active site of the enzyme is the spot where the substrate binds in order for the reaction to occur. The bond formed by the enzyme and substrate is a noncovalent chemical bond that exists little more than a millisecond. However, while bonded the substrate undergoes a chemical change and is converted into the product of the reaction. While held together by this weak bond the enzyme-substrate complex is formed. When the reaction is over this complex breaks down and the product leaves the enzy me and is used by the cell. Then enzyme returns to the catalytic cycle unchanged and it waits to be used again. Any one enzyme may be used over a thousand times per second: in turn requiring very little amounts of enzyme to convert large amounts of substrate into product. Since they are used at such an extreme pace enzymes do wear out and denature. Cellular proteinases are what cause the denaturation of the enzyme. The enzyme is then changed into the most basic amino acids and is used to make other proteins. The balance of the following determines enzyme amount: the process, which degrade the enzyme, and the processes that synthesize the enzyme. If a chemical reaction requires an enzyme to occur and none are present, than the rate of the reaction is very slow. However, if the amount of enzyme concentration is increased in a chemical equation than the catabolic rate is also increased. PURPOSE: The experiment we are going to investigate is meant to determine the effects of temperature on the activity of the enzyme. We will test temperatures ranging from 4?C to 48?C to find out if extreme temperatures either increase or decrease enzyme activity. Four different compounds will be tested, each having a different temperature, in order to determine what, if any, affect those temperatures will have on the enzyme activity. Comparing the color change in the substances will monitor enzyme activity. These color changes will be observed according to their absorbency of light. The absorbency will be monitored using a spectrophometer. Each compound will be tested several times to get an average set of data. This is done in order to avoid skewed results. All raw data will be recorded in table 1.1, and displayed by a graph. The averages will be recorded in table 1.2 and then displayed in there own graph. The averages will be used to get standard deviations. Those figures will be d isplayed in table 1.3 and also displayed in a graph. HYPOTHESIS: Enzyme activity will be increased as the temperature changes. However, at the extreme temperatures the enzyme activity will decrease. One thing should be kept in mind however, this experiment uses peroxidase as its enzyme, but every enzyme has a different optimal temperatures. II. Materials/Method: MATERIALS: 9 test tubes, 2 hot water baths (one at 32?C and one at 48?C), Refrigerator, 30 ml guaiacol, 30ml H2O2, 30ml turnip extract, 30ml of Ph5 stock solution, spectrophometer, micro-pipet, roller pipet, 2 test tubes racks, 2 cuvets, cuvet rack, kim wipes, timer, gloves and goggles, distilled water, micro-pipet tips, sharpie METHOD: 1) Pre-incubate water baths to correct temperatures 2) Label test tubes 1-9 with Sharpie marker 3) Mix test tubes according to table 4.3 on page 4-9 of lab manual 4) Calibrate spectrophometer, according to directions given on page4-5 figure4.3, using test tube number 1 (the control) 5) Mix test tubes 2 & 3 and record absorbency every twenty seconds for 2 minutes. (be sure to start timing as soon as test tubes are mixed being mixed) 6) Mix test tubes 4 & 5 and record absorbency every twenty seconds for 2 minutes. (be sure to start timing as soon as test tubes are mixed being mixed) 7) Mix test tubes 6 & 7 and record absorbency every twenty seconds for