Question

Experiment 2 – The effect of temperature on the activity of catalase

In this lab you will determine the effect of temperature on catalase activity

Materials

Yeast

Measuring spoon

2 clean test-tubes                      

hydrogen peroxide solution

10 ml graduated cylinder

2 balloons

1 beakers

Permanent marker and tape / wax pencil      

stopwatch or timer

crushed ice in a beaker/bowl

Thermometer

Procedure

With a permanent marker, label tubes 1- 2.

Fill each tube with 10 ml hydrogen peroxide.

Place tube 1 in the beaker filled with crushed ice, leave tube 2 at room temperature

Record the temperature of each condition in the table below. Let tubes sit for 15 minute.

After the time has lapsed, remove tubes and place in test tube rack.

Add 5 ml of the yeast solution that you prepared in experiment 1 to test tubes 1 and 2.

Quickly attach a balloon to the top of the test tube.

Swirl each tube to mix, wait 30 seconds.

Record changes in the size of the balloon on a scale of 1 -> 5; 1 being empty , 5 being totally full.

Table 2. Effect of Temperature on the Production of Oxygen
Tube	Temperature degrees ?C	Balloon Circumference (1 -> 5)
Ice bath
Room Temperature

Questions

How does temperature affect enzymatic activity?

Identify the experimental variable in this experiment.

List 2 controlled variables in the experiment.

What is the dependent variable in the experiment?

Answer 1

Answer-1: Temperature is one of the important variable to study the enzyme activity. Enzymes works maximally at their optimum temperature. Optimum temperature for an enzyme is not always 37 degree celcius but it varies with the type of enzyme. Generally, with the increase in the temperature, enzymatic activity decreases due to denaturation of the enzyme. On the contrary, with the decrease in temperature, enzymes gets deactivated because of nearing crystallization point and change in the active site of an enzyme.

Answer-2: Experimental variable is the one that aids in the catalysis process of th reaction. Without it, reaction would not proceed. Therefore, yeast which is a source of catalase is an experimental variable.

Answer-3: Amount of yeast and Amount of H2O2 are controlled variables in the experiment.

Answer-4: Dependent variable of an experiment is the one which usually defnes that a reaction has occured. So, here, in this experiment, it is the amount of oxygen released during the reaction.