Enzymes in the small intestine work better in alkali conditions.
Factors:
Factors that could be changed are:
- Temperature
- Concentration of potato extract
- PH
-
Concentration of Hydrogen Peroxide H2O2
Factor of choice:
The factor I have chosen to variate is the PH level of the Potato Extract.
Apparatus:
Hydrogen Peroxide, Potato Extract (Enzyme-Peroxidase) Filter Paper, 50ml Beaker, Stop Clock, Forceps.
Measurements:
-
The molaity of the H2O2 = 2M
- The timing will be in minutes. (Mins.)
- The mark at which i will fill the Hydrogen Peroxide Solution to = 40ml mark. ( i will be measureing in ML)
- I will drop the filter paper in at 1CM.
Method:
- Get out apparatus
- Put 40 ml of Hydrogen Peroxide Solution in to the 50ml beaker.
- Dip the filter paper, using the forceps, in to the Potato Extract. Remove. Shake, to rid off any excess liquid.
- Hold the paper, with the extract on it, 1cm above the Hydrogen Peroxide Solution and drop it in.
- As soon as the filter paper hits the bottom of the beaker, start timing.
- As soon as the paper reaches the top again, stop timing.
- Record the time it took to reach the top from when it hit the bottom.
- Remove the paper.
-
Dot he experiment exactly the same BUT change the PH of the next Extract you will be using.
Safety Note: Hydrogen Peroxide is corrosive. You should wear safety spectacles when working with the solution. If any comes in contact with your skin or clothes wash immediately under cold water. If you get any in your eyes TELL YOUR TEACHER IMEDIATELY.
Diagram:
Fair Testing:
For a fair test I will keep everything the same except my variable (PH values)
I WILL KEEP:
- The molaity of the Hydrogen peroxide, 2M
-
The amount of H2O2, 40Ml
- The time of which I start timing and finish timing
- The size of the filter paper (this will be very hard to achieve but should be kept the same size for fair testing.)
-
The temperature of the experiment, aprox. 23°
- The same amount of Potato Extract on each square of filter paper. (This also will be very hard to keep the same, but should be kept the same for fair testing.)
…THE SAME TO ENSURE A FAIR TEST.
Prediction:
I predict that the rate of reaction will increase when subjected PH7 (neutral) conditions but will gradually fall as the acidity or the alkalinity of the conditions increase, until when these conditions get too extreme the enzyme will be de-natured and there will be no reaction.
Preliminary Experiment:
Results:
PH 1ST 2ND 3RD AVERAGE
PH 4 NA NA NA NA
PH 6 5.06 secs. 8.92secs. 7.54secs. 7.17secs.
PH8 6.07secs. 7.02secs. 5.47secs. 6.19secs.
In this preliminary experiment I carried out the experiment as if I were doing the real one, so it is exactly the same. After I collected my results I had realized that there was no reaction for the H2O2 with the PH4 Peroxidase. I think this is because the enzyme is de-natured by the acidity of itself. This is backed up by the background information in the introduction.
I have only tested half the of the PH’s so I could only get a rough idea of what the results would be like. I also only tested the even numbers because they were the numbers that were around the middle so I could get a good idea of what the rest of the results would look like.
Preliminary Graph:
Results:
1st 2nd 3rd Average
PH4 NA NA NA NA
PH5 5.79secs. 5.28secs. 4.06secs 5.04secs.
PH6 8.79secs. 8.70secs. 5.96secs. 7.81secs.
PH7 6.37secs. 6.34scs. 7.05secs. 6.58secs
PH8 6.53secs. 5.
PH9
