The enzyme has an active site that helps it to recognise its substrase in a very specific way. Just like a key that only fits into a certain lock , each enzyme has its own specific substrase.This is called the lock and key theory,the diagram below shows this.
The digestion of carbohydrates is performed by various enzymes. Amylase, found in saliva and in the intestine, breaks starch, dextrin, and glycogen into maltose, a 12-carbon sugar.
Enzymes are large proteins that speed up chemical reactions. In their globular structure, one or more polypeptide chains twist and fold, bringing together a small number of amino acids to form the active site, or the location on the enzyme where the substrate binds and the reaction takes place. Enzyme and substrate fail to bind if their shapes do not match exactly. This ensures that the enzyme does not participate in the wrong reaction. The enzyme itself is unaffected by the reaction. When the products have been released, the enzyme is ready to bind with a new substrate.
I predict that as the temperature gets higher reactoins will get quicker,but at a cretain high temperature the reactions will slow down again due to to enzyme becoming denatured.I believe that at temperatures lower than body temperature will prevent reactions taking place as quickly because at lower temperatures particles collide less therefore the reaction is slower.
Plan and method
I must make sure the test is fair to ensure i gain accurate readings.I will gain accurate readings by keeping the following variables constant:
- Volume of amylase;
- volume of starch ;
- Time ,how long is left between each test for starch;;
- volume of iodine ;
- pH of the amylase and starch.
The factors listed above would affect the experement and need to be controlled.
We will not use repeat readings because a limited amount of time will be given forthe experement.We measured the rate of reaction during the experement in minutes.We measured how long it takes for the amylase to completely digest the starch and turn it into sugar.,Although we did not use repeat readings they would be usefull in obtaining a better and more accurate ste of readings.If there was human errors during the experement repeat readings would help gain a clearer result.We did not change any volumes of solution during the experement.
In the experement we used pipettes, 4ml,spotting tile,thermometer,test tube,bunsen burner,tripod ,guaze and heatproof mat .
For safety we used gogggles and a heatproof mat as we were dealing with fire.
This is a step by step account of the experement:
1-We recorded room temperature;
2-We added two drops of iodine into each well of the spotting tile:
3- A beaker was half filled with water:
4-3,ml of amylase was put into one test tube and 6ml of starch was added into another ;
5-All the substances were heated to the same temperature then the amylase was added to the starch
6-We started the stop watch and tested for the presence of starch after every minute for 10 minutes;
7-We tested for the presence of starch by adding the solution to iodine,if the iodine turne dblack starch was present;
8-we recorded our results in a table.
We cariried out the experement three more times at different temperatures.
Diagram of apparatus:
We waited for all apparatus to cool before packing them away as not to burn the skin.We used the apparutus with accuracy by using the scale on the sides of the beaker and pipettes.
Results
