RP investigating enzymatic reactions

Question 1

describe the method

Answer 1

1. Set up a water bath at 30°C.
2. Measure out 5 cm³ of starch solution, 1 cm³ of amylase solution and 1 cm³ of a buffer solution with pH 5 into a boiling tube and place into the water bath for 10 minutes.
3. Place a drop of iodine solution into each well on a spotting tile.
4. After 10 minutes, combine the solutions into one boiling tube and stir, add one drop to the tile with iodine then start a stop clock.
5. Every 30 seconds, using a pipette, transfer one drop of the solution onto the spotting tile containing iodine.
6. Continue taking samples of 30 seconds, until the iodine solution remains a browny-orange colour and record the time taken. This shows that starch is no longer present.
7. Repeat with different buffer values to see how pH affects the time taken for the starch to be broken down.
8. Calculate rate of reaction using 1/time taken.

Question 2

list the equipment

Answer 2

boiling tube
water bath
spotting tiles
measuring cylinder
a glass rod
a stop clock
buffer solution
amylase solution
iodine solution

Question 3

rate of reaction equation

Answer 3

1/time

Question 4

why must samples be left in the water bath before solutions are mixed?

Answer 4

so the temperatures are the same

Question 5

what is a buffer solution?

Answer 5

a solution which can resist changes in pH