About Me

My photo
My name is Poon Cheng Moh. I have been teaching biology in SMK(P) Raja Zarina, Port Klang for 26 years. I sincerely hope that this blog on SPM Biology will be useful to both teachers and students.

Saturday, April 23, 2011

Answer to Bioscore pg 78-79/ Hands on pg 42

2. Plan an experiment to study the effect of enzyme concentration on the activity of an enzyme.

Objective

To study the effects of enzyme concentration on the activity of salivary amylase.

Problem Statement

What are the effects of enzyme concentration on the activity of salivary amylase?

Hypothesis

The higher the enzyme concentration, the higher the rate of reaction until it reaches a maximum rate.

Variables

Manipulated: Enzyme concentration

Responding: Time taken for the complete hydrolysis of starch//Rate of reaction //Activity of enzyme

Fixed : Substrate concentration// temperature// pH

Materials & Apparatus

Materials :1% starch suspension, 0.2%, 0.4%, 0.6%, 0.8%, 1.0%, 1.2% amylase, iodine solution and distilled water.

Apparatus : 5 ml syringe, 1 ml syringe, test tubes, glass rod, stopwatch, white tile with grooves, measuring cylinders and dropper.

Technique

Measure and record the time taken for the complete hydrolysis of starch using a stopwatch.

// Calculate the rate of reaction using the formula : (1/time taken for the complete hydrolysis of starch).

Procedure

1. 6 test tubes were labelled as A, B, C, D, E and F and put in a water bath at 37oC.

A : 1.0 ml 0.2% amylase

B : 1.0 ml 0.4% amylase

C : 1.0 ml 0.6% amylase

D : 1.0 ml 0.8% amylase

E : 1.0 ml 1.0% amylase

F : 1.0 ml 1.2% amylase

2. Each test tube was filled with different volumes of amylase as given above.
3. A few drops of iodine were dropped separately on the grooves of a white tile.
4. 4 ml of 1% starch suspension was poured into test tube A.
5. The stopwatch was started. A small amount of mixture was added to the drop of iodine on the white tile immediately.
6. The colour change in iodine was observed.
7. The iodine test was carried out at an interval of 30 seconds until there was no more change in iodine colour (colour remained yellow).
8. The time taken when the colour of iodine remained yellow was recorded.
9. Steps 4-8 were repeated for test tubes B, C, D, E and F.
10. All observations were recorded.
11. A graph of rate of reaction (1/time) against enzyme concentration was plotted.

Results

Concentration of amylase (%)

Time taken for the complete hydrolysis of starch (minutes)

Rate of reaction

(1/time) (min-1)

0.2



0.4



0.6



0.8



1.0



1.2



Conclusion

Hypothesis is accepted. The higher the enzyme concentration, the higher the rate of reaction until it reaches a maximum rate.





No comments:

Post a Comment