Effect of Temperature on Enzyme Catalase Activity in a Potato

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Effect of Temperature ( C ͦ) on Enzyme Catalase Activity in potato

Aim: To investigate the Effect of temperature (10, 37, 60) Celsius (C ͦ) on enzyme catalase activity in potato using 2% of hydrogen peroxide (H202) as the substrate measuring the height (cm) of oxygen gas (bubbles) and calculating the volume of oxygen bubbles produced (cm3) Introduction: Enzymes are biological catalysts that speed up metabolic reactions without being affected. They lower the activation energy needed to start a reaction.Enzymes are affected by several factors including PH, Substrate concentration; Temperature & other factors. Each enzyme has an optimum temperature at which its activity is the highest, below this optimum temp, the kinetic energy of molecules decrease , therefore the collisions between the active site of the enzyme and substrate decreases , as a result the enzyme activity will decrease , so decreasing the rate of the reaction If the temp. Exceeds the optimum temp. The kinetic energy between molecules increase therefore collisions increase leading to the change in the tertiary structure of the enzyme and in this case active site is lost and the enzymes will be denatured so the reaction will slow down &stops. Catalase is an enzyme, found basically in all living cells. It breaks down hydrogen peroxide (waste product) into water and oxygen.

2H₂O₂ 2H2O+O2
As predicted, the enzyme catalase activity would be the highest at 37c ͦ (Optimum temp.)if increased to 60c ͦ then the enzyme would be denatured and if decreased to 10c ͦ (very low temp.) then the reaction would be slow. Variables:

Dependent: Height of oxygen bubbles (cm) using a ruler.
Independent: Temperature (10c ͦ, 37c ͦ, 60c ͦ) using three different water baths each adjusted to a specific temp . Controlled:
1. Number of potato cubes: 3 cubes of potatoes were used in each trial at each different temp. If changed, whether decrease or increase, then the number of enzymes (active site) available would change, therefore affecting the rate of the reaction. 2. Size of potato cubes with dimensions 1cmx1cmx1.5cm .This is controlled by cutting all potato cubes with same dimensions using a ruler & a cutter. If changed, then this would affect the rate of enzyme activity, therefore affecting the results. 3. Volume of hydrogen peroxide: 15cm3 of hydrogen peroxide was measured using graduated cylinder for each trial at different temp. If changed then the rate of enzyme activity would change, therefore results won’t be accurate. 4. Concentration of hydrogen peroxide: 2% of hydrogen peroxide was used through all trials this is prepared by adding 20cm3 of H2o2 to 1000cm3 of water. If changed it would affect the rate of enzyme activity since substrate concentration is one of the factors that affect enzyme activity. 5. Volume of liquid detergent: 2drops of liquid detergent were added to each test tube throughout the experiment. If changed, then this will affect the height of oxygen bubbles measured cm3 therefore the results won’t be accurate. 6. Time: time was recorded for 2 minutes; if changed this will affect the results.

Materials:
* 27 cubes of potato each with dimensions 1cmx1cmx1.5cm.
* 15cm3 of 2% hydrogen peroxide for each trial.
* 9 test tubes
* Water adjusted to (60c ͦ,37c ͦ&10c ͦadding ice) * 2drops of liquid detergent in each test tube
* Cutter
* Ruler
* 100cm3 graduated cylinder
* Stopwatch
* 1000cm3 volumetric flask
* 50cm3 beaker

Procedure:
1. Use the cutter, and ruler to cut 27 cubes of potato with dimensions 1cmx1cmx1.5cm 2. Adjust the water bath temp one at 60c ͦ, the other one at 37c ͦ & last one at 10c ͦadding ice. 3. Place 3 potato cubes in each of the three test tubes placed at 10c ͦ. 4. Leave the test tubes at 10c ͦfor 10min.

5. Add 2 drops of detergent for each test tube.
6. Measure 15cm3 of 2% hydrogen peroxide for each test...
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