1.
Each enzyme has an active site into which its substrate molecule fits exactly. This enzyme is amylase, and its active site is just the right size and shape for a starch molecule.
2.
The substrate molecule (starch in this case) slots into the active site.
3.
The starch molecule is split into maltose molecules. The enzyme is UN altered, and ready to accept another part of the starch molecule. I received my research from books called biology by Jones and Jones.
Prediction
I predict that the temperature will affect this rate of reaction:
Yeast + glucose Energy + CO2
(Zymase) + Alcohol
I also predict that for every 10’c increase in temperature then the reaction will double. This is important because the higher the temperature the faster the particles move about and the more likely they are going to collide successfully. I used the word successfully because when they collide they need enough energy to work and if they don’t have enough energy then nothing can happen. But unlike an ordinary chemical reaction this is a biological catalyst and it doesn’t increase. I also predict that the enzyme molecule will brake down the substrate molecule like this:
1.
This shows an enzyme molecule and a substrate molecule.
2.
This shows the substrate molecule slotting exactly into the activation site.
3.
This shows that the substrate molecule has been broken down.
I also predict that during the experiment it will reach its optimum temperature. Its optimum temperature is when it reaches its highest point. I also predict that after it reaches the optimum temperature then its rate of reaction will slow down this will happen because the enzyme is starting to denature. Denaturing is when the temperature reaches its highest point for the enzyme to work and then the reaction slows down.
I predict that my results formed into a graph will look like this:
Fair Test
I will make it a fair test by using the same type of yeast-as some may have different surface areas than others, use the same type of glucose because the particles may vary, use the same ph because it would affect the enzyme, use the same burette as it has the same calibrations, use the same apparatus throughout as it may cause anonymous results if you don’t and most important make sure the readings are taken at the right time and temperature.
Results
Volume of CO2 :
Number of bubbles:
Apparatus
Method
We are going to measure the rates of reaction in yeast. We are going to measure the amount of carbon dioxide produced. The carbon dioxide is produced when the reaction has taken place. We are also going to count the amount of bubbles that go up the inverted burette.
We will start the experiment firstly by putting some yeast in a boiling tube and seal it. We will put the yeast in water firstly at 20oc then we will count how many bubbles are given off, and how many Cm of water in the burette goes down. I will do this 5 times for 20oc and then I will heat it up to 30oc and do the same processes. I will heat it up each time by 10oc. I will record all my results in a table shown overleaf.
Analysis
In the experiment we took the readings 5 times at 20oc. The volume of CO2 and the amount of bubbles that were produced at this temperature was 0. This is because the enzymes are dormant. So after that, I heated it up to 30oc and the yeast started to give off carbon dioxide. This meant the particle in the enzyme start to collide, this also meant that there was enough energy in the collisions for a reaction to take place, and this is called activation energy.
Then after I had taken all the results at 30oc, I heated it up to 40oc. At this temperature there was more C02 given off because the water in the burette went. Then after I had took all five readings for that temperature, I then heated it up by 10oc to 50oc. When I heated it up to 50oc there were even more collisions happening because there was more C02 given off than there was at 40oc. This could be the optimum temperature. We will find out when we heat it up 10oc more. So I heated it up by 10oc after I had took all five readings at 50oc. At 60oc there was less bubbles meaning less C02 given off. This is a sign that the enzyme is starting to denature. So to see if it is, I heated it up again by 10oc and even less C02 was given off. After taking the second reading there was no C02 given off this means the enzyme is denatured. So that meant that 50oc was my optimum temperature. So to my prediction, I said for every 10oc rise in temperature it will double the reaction. This did not happen so I was wrong.
On my graph I have drawn there were anomalous results, I have identified these by circling them.
Evaluation
The apparatus I used had a small scale so they would be accurate, and I tried to make it a fair test, by taking 5 reading and using the average to make a graph, and I still got anomalous results. The experiment was very difficult to perform, because you had to watch for bubbles and write down your results as well. That’s why I used a table to record my results so it was quick and easy to record. It was also hard to count the volume because the burette was upside down. It would have been more accurate if I used a gas syringe. Also a plastic tube was not airtight so I put Vaseline around the top to stop gas escaping. The tube could easily get blocked if the burette went down to the bottom of the water, and trapped the tube squeezing it together, so if I did the experiment again I would uses a gas syringe and maybe different types of yeast and sugar as well.
