To investigate the denaturation of an enzyme by heat.

PROCEDURE

1. Place yeast solution in a beaker and place into the water bath at 100⁰C.
2. Add the heated yeast and the buffer to a graduated cylinder.

3. Add  hydrogen peroxide to another cylinder.
4. Stand the cylinders in a water bath until the desired temperature (25⁰C) is reached

5. Add the hydrogen peroxide into the cylinder containing the yeast and buffer.
6. Note the presence or absence of foam formation and record.
7. Repeat the experiment with yeast solution that was not boiled and compare results.

2008 Q9

Sample Answers

2008 Q9

1. i – the pH at which the enzyme works best

ii – a denatured enzyme experiences a changed shape and loss of function

2. i – enzyme used – catalase

ii – substrate – hydrogen peroxide

iii –

1. 1In one graduated cylinder add hydrogen peroxide
2. To the other, add enzyme, pH10 buffer  and washing up liquid
3. Place cylinders in water bath of boiling water for 10 minutes
4. Control – place cylinders with identical content into water bath at 20 degrees for 10 minutes
5. Mix tube A and Tube B.
6. Start stopwatch and record foam  at 2 minute intervals

*draw a diagram if needed*

Iv – Control – bubbles form as oxygen is produced

Denatured enzymes don’t produce bubbles as no reaction occurred to produce oxygen