For my preliminary work, I was aided by a computer simulator which simulates this experiment so that I could determine what variables I could change for my experiment so that ultimately, I would have a set of numerical results, that I would be able to compare and analyse. The software I used was very helpful as it helped me decide the number of potatoes that I would use and the time I would allow the enzyme to react. I also have relative, scientifically accurate preliminary results which signal that my experiment would be quite successful and I was able to determine a hypothesis using my preliminary results and background knowledge.
I followed the preliminary experiment with an actual experiment which was also preliminary. In this experiment, I was able to determine the successes of the computer aided simulator by testing out what I have decided to do.
Here are the results and my analysis of my preliminary results. The first variable I investigated was the time to allow the chemical reaction to take place. I used 5 slices of potatoes and tested each at temperatures ranging from 10 Degrees Celsius going up 5 Degrees Celsius respectively until it reached 60 Degrees Celsius. I collected results from the simulator for 1 minute, 5 minutes and 10 minutes. My results can be shown in fig. 1. After analysing my result, I came to the conclusion all three times of collection was adequate for the experiment in question. Therefore I decided to use 5 minutes, as it is in the middle, and the results that were collected were more evenly spread out. Gases can be measured in 3 ways; mass lost, into a syringe or under water, my practical preliminary saw successes using the gas syringe. Therefore it is what I would use.
From my research, I have found out that Enzymes may work faster if the temperature within the cell increases as the molecules travel faster as it heats up, but if the temperature increases too much, the living cell may die and they may breakdown called denaturation. The most effective time when an enzyme works is called the optimum temperature which is 36 degrees Celsius, usually, the optimum temperatures for enzymes in living cells are close to the normal cell temperature.
Reactions occur when particles collide with enough energy (activation energy) as the temperature becomes higher the particles move faster around and collide to cause the chemical reaction. Enzymes are protein molecules produced by living cells. Catalyse is an enzyme found within living cells of organisms. It chemically processes the breakdown of hydrogen peroxide into water and oxygen.
Hydrogen Peroxide (aq) Water (aq) + Oxygen (g)
2H2O2 2H20 + O2
This reaction is a necessity, as H2O2 is continuously produced by poisonous metabolically active cells, these must be got rid off. Catalyse is an enzyme and can speed up the reaction up to 10,000 times. One molecule of enzyme combines with 10,000 molecules of hydrogen peroxide / second. Without enzymes, chemical reactions would be very slow.
`Researching, I have found that Catalyse is the most active enzyme known, which works on a single substrate and is affected by environmental conditions, for example, temperature or pressure.
With regards to my experiment, the environmental condition that I will alter is temperature.
The following are the equipment that I will be using;
- Gas Syringe- to collect the gas produced from the reaction.
- A beaker-to put water in and bathe test tube in.
- Test tube- to hold and combine the H²O².
- Thermometer-to record temperature.
- Syringe holder- to hold the gas syringe while collecting gas.
- Boss and Clamp- To hold the syringe holder to the retort stand.
- A stop clock- to time reaction.
- Delivery tube- to connect to the test tube and syringe to collect the gas.
- Knife- to cut the potato to our requirements.
- Tile- to cut the potato on so that our work surface area does not get defaced.
- Cork borer- to make sure that each time we use the same amount of potato.
- A potato
- 10ml of H²O²
Diagram
I predict that the enzymes would work better as the temperature becomes higher; however, passing the optimum working level, of 36 Degrees Celsius, I predict that the rate would slow down. I am basing my hypothesis on the ‘lock and key’ theory uses the idea of the enzyme as a lock, and the substrate as the key. Only the correct key will fit in the lock, so only the correct substrate will react with the enzyme. If the temperature is higher than a certain point, chemical reactions cannot take place effectively or at all.
Here are my results.
My experiment went very well, from my results, I could see that the ‘loop’ pattern I was expecting in the graph is present. I think that if I were to reattempt this experiment, I would change the variables. I could vary the time of the reaction or change the amount of slices of potatoes that I use. Improvements I could make are trying to do the whole investigation on the same day therefore the conditions in which I conduct my experiment would be more suitable and fairer in terms of fair testing.
I think that the results are very good. I think this because the average results showed what I said in my prediction. I said that the largest amount of gas collected would be around 36 degrees Celsius. This is satisfied in my results.
In conclusion I think my experiment went relatively smoothly, my results must be quite good because I got my prediction correct.
