internal assessment enzyme

Dependent        :        Rate of amylase reaction on starch by taking the time measurement                                 for the starch to react with the amylase enzymes.

Constant        :        Volume of the starch by taking 5ml of the starch to be put into the                                 test tube for each experiment.

MATERIALS AND APPARATUS

(Please refer to biology handbook page 64)

METHOD

(Please refer to Biology handbook page 64 and 65

DATA COLLECTION

Qualitative data

1. Cloudy solution of mixture of amylase solution and starch solution turn colourless after some time.
2. At first, the colour of the mixture added to the drops of iodine is dark blue, but soon afterwards it gradually into the original colour of the iodine drops.
3. There is a constant blue-black colour change for the control experiment.        

Quantitative data

• Volume of  starch solution used in each test tube :5.0±0.05 cm3
• Volume of enzyme amylase use in each test tube : 5.0±0.05 cm3
• The amount of iodine used in each hole of white tile : 2 drops
• The amount of starch-enzyme solution used in each hole of white tile : 2 drops

                        Table 1 : the time taken for starch to hydrolyse completely

           Table 1 : time taken for starch to be hydrolysed completely in different temperature

DATA PROCESSING

The average reading from 2 sets of experiment is taken using the formula

                        

Table 2 : the average reading for the time taken to completely hydrolyse starch

The rate of enzymatic reaction of amylase enzyme can be calculated using the formula : 
where `t’ is the time taken for starch to completely hydrolyse.

Uncertainties of rate of reaction, ∆R =  × R

      Where, t  = time taken for iodine to change its colour from dark blue to brown

                    ∆t  = uncertainties of t

                    R  = rate of reaction of amylase enzyme on starch

           Table 3 : rate of reaction of amylase enzyme to hydrolyse starch completely

         Graph 1 : rate of enzymatic reaction against temperature

CONCLUSION AND EVALUATION

The first temperature recorded is 5°c and the rate of reaction for amylase enzyme is the lowest during this temperature neglecting the rate of reaction at 100°c. Next, with the increment of temperature, the rate of reaction continue to increase until a point is reached  which is the optimum level at °c. Then the curve shows a negative gradient which indicates that the rate of reaction for amylase enzyme is decreasing until point where 100°c is reached. Here the rate of reaction is zero and this value shows us that there is no more enzyme because all of it has been denatured due to very high temperature.

The hypothesis is accepted as the temperature of starch and amylase enzyme increase the rate of reaction will be increased until the optimun temperature and the rate of reaction decreased when the temperature of  mixture of amylase enzyme and starch is above the optimum temperature.