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.