Prediction
I predict that as the temperature increases the amount of oxygen produced will increase. When the particles are warmer then they have more energy and move around more therefor they are more likely to collide with each other. I predict that when we test the enzymes at 60°C, the amount of oxygen produced will be low, because I know that enzymes denature at about 60°C. When we test it at 15°C I predict that the oxygen produced will be higher that 60°C. The enzymes will probably produce more oxygen at 40°C because that is the nearest temperature to body temperature. Body temperature is 37°C and I think that enzymes are designed to work best at this temperature. I predict the higher the concentration of the hydro peroxide; the more oxygen will be produced, because the enzymes will have more hydro peroxide to break down and in my background information it says if there If too little substrate is available the rate of the reaction is slowed. If the enzymes are in there specific optimum, when they have a high enough substrate concentration for the reaction they catalyse, they will be producing more oxygen.
Pre-testing
Pre-testing is done to get an idea of what the actual experiment results are going to be, so if the real experiment isn’t like the pre-test results then, something went wrong during the experiment.
For this pre-test, we had 5ml hydro peroxide and 5 pieces of the same pigs liver cut up. We decided to dilute the hydro peroxide and put 1 piece of liver in. We decided to measure the height of the bubbles in the test tube. This can show us the amount of oxygen produced because the bubbles will be the oxygen. We aren’t being completely accurate the pre-testing will only tell us which concentration level is better. The other input variable we had decided on was the temperature. We couldn’t get the equipment needed for the changing of the temperature.
These were the results:
These results show that the higher concentration of the hydro peroxide the more bubbles/oxygen produced.
Apparatus
- Measuring cylinders
- Test tubes
- Tubes
- Test tube connector
- Water bath
- mortar and pestle
- stop watch
Method
We have calculated that we will be collecting 22 pieces of data. We are going to be using 2 different sources for our catalyse enzymes; we are using enzymes from a liver and some enzymes from a potato. The first method is for the liver enzyme results.
To start with we will first have to get the enzymes. To do this we will grind up a piece of pigs’ liver with water and sand in a mortar and pestle. Then we will filter the mixture to get the sand and solid bits of the liver out. We will then take the amount of liver mixture with enzymes in that we need and bring it to the temperature that we need it at for our variables by putting the test tube in a container of water at the temperature we need. We will also do this with the amount of hydro peroxide and water we need.
Then we will fill a tube up with water and put a glass 10ml test tube under the water, making sure it doesn’t have any air bubbles in it. Then connect the test tube in the water, with the one with 1ml of enzyme solution in it. Then we will add the hydro peroxide and put the stopper in as quickly as possible so we do not lose any oxygen and then wait for 20secs. We will then measure how much oxygen has been collected in the glass test tube under the water in cm.
When we had to do the concentration of the hydro peroxide we will simply keep the amount at 5ml and change the amount of water and hydro peroxide like 4ml water and 1 ml hydro peroxide, 3ml water and 2ml hydro peroxide etc.
When we do the temperatures of 40°C and 60°C we will have to put the test tubes with hydro peroxide solution and enzymes in a water bath, so to maintain the temperature we need. When we do 15°C we will have to add ice to our tub and put the test tube in that until it is at the temperature we need.
For the potato enzyme experiment we did the same apart from replacing the liver with pieces of potato and grinding that up with sand and water instead. Also only doing the temperatures of 15°C and 60°C. We will add ice into the 15°C and we shall put the test tube in a water bath for 60°C.
Fair testing
To make sure our results will be fair we will make sure the enzyme solution and hydro peroxide solution are at the same temperature as each other when we do the experiment. We will try and put the stopper in as quickly as possible, to prevent loosing the oxygen produced in the first few seconds. We will make sure we use 1ml of enzyme solution each time. Also we will use the same potato and liver solution for each experiment so that the self-life and age of the animal/ potato don’t change. We will also make sure the glass test tube doesn’t have any oxygen in it before mixing the hydro peroxide and enzymes making it not a fair test.
Results
Liver enzymes
15°C
20°C
40°C
60°C
Potato Enzyme:
15°C
60°C
Conclusion
The results show that more oxygen was produced at 15°c with the liver enzymes and potato enzymes. I would not have expected this because I would have expected it to produce more in the 40°c test. The reason I would not expect it to produce the most oxygen at 15°c is because it is a low temperature and enzymes normally react more at the temperature it is used to, body temperature or the 40°c in our test. The temperature at which the second most amount of oxygen was produced at is 20°c. As the temperature went up the amount of oxygen went down.
I was expecting it to go as the temperature went from 15°c to 20°c to 40°c the amount of oxygen would increase then it would peak at the 40°c then go back down on the 60°c test but it did not. This might have been because we were doing something wrong or we just had a weird piece of liver.
When we got to the last concentration for the liver enzyme at 60°c we found we did not have enough enzyme left to do the experiment so instead of liver enzyme we tried potato instead. This showed us that not much oxygen was produced, the first two concentrations didn’t produce enough oxygen to be measured with what we were measuring with, so the enzymes might have started to denature at such a high temperature.
The potato enzymes produce more oxygen at 15°C this may be because the enzymes denatured at 60°C.
More oxygen is produced when the concentration of the hydro peroxide is high, or pure this has happened with both enzymes and all the different temperatures.
The potato enzymes did not produce as much oxygen meaning that the enzymes were not as strong or there weren’t so many.
Evaluation
In this investigation we didn’t manage to get a second set of results, because we didn’t have enough time. This affected the results because we might have made a mistake and doing it a second time we could have spotted it and got an average.
The only anomalous result I think we had was one of the liver enzyme at 60°C, with 2ml hydro peroxide and 3ml water, this had made 10.2ml of oxygen, the result for the 1ml of hydro peroxide and 4ml of water was only 0.8ml. I would have done this one again if I had noticed then that it did not fit in with the other results.
Some of the results may not be correct because we did not get the stopper in as quick as we did for the rest of them we couldn’t help this.
The 60°c potato test the first two outcomes were two small to measure with what we were measuring with.
When we ran out of liver enzyme we did not get more liver because it would not have been the same liver and would not have had the same animal age, shelf life or had the same amount or strength of enzymes.
If I was to do this experiment again I would collect 5 pieces of data for each one instead of 3 this would give us more back up if one result was wrong and we could have seen if it fitted into the pattern. I would also make sure I have enough enzyme solution to do all the experiments. I would also have done each test 3 times to get an average.
If we wanted to really be accurate with how much oxygen was produced we would have used a gas syringe but we did not have access to these.
Our results showed that the higher the temperature the less oxygen produced I don’t think this is right. To extend the experiment we could change some of the control variables. Some of these would be hard to do like the pH.
All together I think we could improve what we did a lot.