Amylase is an enzyme that catalyses the breakdown of starch into sugars. Amylases are found in almost all plants, animals and microorganisms. Large amounts of amylase occur in germinating cereals, and in the pancreas and saliva of higher animals.
The aim of this experiment is to find out the rate of reaction between amylase and starch in a range of different reaction temperatures.
As the reaction temperature of amylase solution and starch solution increase, the reaction rate of amylase and starch will increase. After reach the optimal temperature of amylase, the reaction rate of amylase and starch will rapidly decrease.
The lock and key model explains my hypothesis. Most enzymes are very specific for a certain substrate, the active site on the enzyme molecule forms a "keyhole" into which the substrate fits like a key, the substrate molecule is then broken up into many smaller pieces. The higher reaction temperature, the more kinetic energy the substrate molecules will have. It means that the molecules can move faster and have a greater chance to collide and react. However, if the reaction temperature is too high, enzyme may become denatured. Denaturation is a structural change in a protein that alters its three-dimensional shape and causes the loss of its biological properties1. As the temperature rises the amount of active enzyme progressively decreases, and the rate of reaction is slowed. So there should be an optimal temperature for each enzyme.
How does a range of different reaction temperature (0°C, room temperature during the experiment, 40°C, 60°C, 80°C) effect on the rate of reaction between amylase and starch?
Dependent variables: the required time for the disappearance of blue-black color (color of Iodine solution mix with starch solution ).
Independent variables: reaction temperature (0°C, room temperature during the experiment, 40°C, 60°C, 80°C).
Significance/effect if not controlledMethod of control Volume of amylase solution in each test tubeThe volume of amylase solution in each test tube needs to be a constant number, because we do not know if this variable will affect result. To ensure that the result is accurate, it is necessary to maintain same volume of amylase solution in each test tube. So that the reaction temperature will be the only independent variable influence the required time for the disappearance of iodine color.Using same measuring cylinder and read accurately. Volume of starch solution in each test tubeThe volume of starch solution in each test tube should be the same. If not, the rate of reaction between amylase and starch will be affected. Some test tubes which have more starch solution than others may decrease the time required to reach the reaction temperature. And also, the rate of reaction between amylase and starch will be affected because it may take more time to completely break down starch molecules if there is more starch solution. The required time for the disappearance of blue-black color in test tubes will become inaccurate.Using same measuring cylinder and read accurately. pH valueChange in pH can have a dramatic effect on the rate of amylase –catalyzed reaction. This effect of pH is because the structure of a protein is maintained by various bonds within the three-dimensional structure of the protein. A change of pH from the optimum values alters the bonding patterns, progressively changing the shape of the molecules. If the molecules are denatured, the reaction cannot happen, the result will become unreliable. pH value will be a new independent variable if it is not controlled.Using pH test strips to test the pH value of amylase solution and starch solution before the experiment. Concentration of amylase solution in each test tubeConcentration of amylase...