Catalase Enzyme Lab

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Catalase Enzyme Lab

Samiya Hussein
March 9, 2012

Introduction
In order to receive the necessary amounts of energy required for daily function, the digestive system must break down proteins, fats and carbohydrates. In doing so, the body produces poisonous chemicals; however, the cells aren’t harmed. This is because enzymes are used to break down these chemicals. The name of the enzyme that was the main focus of the lab is catalase. Catalase is responsible for catalyzing hydrogen peroxide into oxygen and water. Since hydrogen peroxide is continuously produced by numerous metabolic reactions, catalase helps to prevent the body tissues from being damaged by the peroxide. pH is used to measure the acidity or basicity of a solution and is very important when chemical reactions are concerned. A value of 7 is neutral while a pH of less than 7 is acidic and a greater pH than 7 is basic. This scale is logarithmic, which means that for every increase or decrease is 10 times more or less acidic/basic than before. In the human body, optimal pH levels range from 7.35-7.45, any changes out of this range can be detrimental to one’s health.

Problem
The questions being asked in this lab are: Is catalase reusable? What are the optimal conditions for catalase? How does the activity of catalase compare in liver and other tissues? Hypothesis
Part A: If the liver is placed in 2 ml of 3% hydrogen peroxide, then the result will be a high rate of reaction because catalase reacts with hydrogen peroxide to form hydrogen and oxygen. If pieces of potato, chicken, and apple are placed into 2 ml of hydrogen peroxide separately, then the chicken will have the highest reaction Part B: If the liver is placed in 2 ml of 3% hydrogen peroxide at room temperature, then there will be a high rate of reaction. If the temperatures are at extremes, the enzyme will be denatured and therefore won’t catalyze the hydrogen peroxide. Part C: If the pH is neutral, then the enzyme will react properly with the 3% hydrogen peroxide. If it the pH is at extremes, the enzyme will be denatured and therefore won’t catalyze the hydrogen peroxide.

Materials

-6 small liver pieces
-3% hydrogen peroxide
-6 ice cubes
-Small drops of NaOH as needed
-Small drops of HCl as needed
-1 hotplate
-1 small piece of an apple
-1 small piece of chicken
-1 small piece of a potato
-3 test tubes
-1 test tube rack
-1 pipette
-1 beaker
-1 tweezers
-1 pair of tongs
-2 stirring rods
-3 strips of pH paper
-2 droppers

Procedure
Part 1
Place 2 ml of the 3% hydrogen peroxide solution into a clean test tube. With tweezers, pick up a piece of liver and place into the test tube. Push the liver slice into the hydrogen peroxide with the stirring rod and observe the reaction. Place 2 ml of the hydrogen peroxide solution into a clean test tube and again add a small piece of liver and observe the reaction. Then pour off the liquid into a second clean test tube. Add a piece of liver to this used liquid and observe what happens. Then, add another 2 ml of hydrogen peroxide to the liver remaining in the first test tube and observe what happens. Place 2 ml of hydrogen peroxide into a clean test tube. Then cut a small piece of potato and add it to the solution and record what happens. In another test tube add 2 ml of hydrogen peroxide and a small piece of chicken. To a third test tube, add a small piece of apple and 2 ml of hydrogen peroxide. For each, observe and record the reaction.

Part 2
Put a piece of liver into the bottom of the clean glass test tube and cover it with a small amount of the distilled water. Fill one of the beakers with water and put it on the hot plate to boil. When it begins boiling, place the test tube into the boiling water bath for 5 minutes. Using the test tube holder, remove the test tube from the boiling water and allow it to air cool. Then pour out the water into the waste container and add 2 ml of hydrogen peroxide to the boiled liver. Observe...
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