Yeast Enzyme Lab Report

Megan Roe 12OMT

Aim:

To investigate the effect of pH of hydrogen peroxide solution on enzyme activity of the catalase enzyme (yeast) and the O2 froth produced (ml) after 1 minute.

Hypothesis:

That an increase of hydrochloric acid to a solution where yeast cells are exposed will increase the rate amount of enzyme catalase (O2 froth) produced, as from my research it has been proven that with some enzymes the optimum pH is around 2 (stomach enzymes).

Variables:

Independent Variable: pH

The independent variable being used in this experiment is pH, and the effect it has on enzyme activity.

The range of pH I am using is 5 different pH levels (2,4,7,9,12), this range covers all of the important pH levels that I need for this experiment, including

This can be checked by using a thermometer with each substance.

Method:

Tape a ruler to a wall at eye level.

Make sure all substances being used ar at room temperature (37℃) with a thermometre

Measure out 1 ml of the Hydrogen Peroxide (H2O2) solution with a plastic pipette, then transfer to a clean boiling tube.

Repeat this another two times into two other boiling tubes.

Add to each three boiling tubes 1 ml of the pH buffer solution being used first (hydrochloric acid or sodium hydroxide) with the pipette for, and pour into a boiling tube with the Hydrogen Peroxide solution.

Use a pipelette to gather some of the mixture out of the three boiling tubes and place one drop from each boiling tube into three separate tile spotters.

Use one drop of universal indicator on each solution in the tiles spotters to determine the correct pH that is needed for the first reaction (either 2,4,7,9,12).

Add to each three boling tubes 1 ml of yeast, and start a timer as soon as the yeast is transferred to the boiling tubes.

Time each boiling tube for 1 minute, then measure the O2 froth produced from the solution with a ruler at eye level.

Repeat above steps 5 times for each pH level