Required Practical: Enzymes Flashcards
All 6 cards in this deck
What are the steps to investigate the effect of pH on the rate of reaction of amylase?
e.g. testing amylase at pH 5- Mix amylase, starch and pH 5 buffer in a tube in a water bath at a set temperature.
- Every 30 seconds, put one drop of the mixture into iodine on a spotting tile.
- Record the time when the iodine stays orange-brown — the time to digest all the starch at pH 5.
In the amylase practical, how do you know all the starch has been digested?
The iodine stays orange-brown instead of turning blue-black.
Why is a water bath used when investigating the effect of pH on amylase?
To keep the temperature constant, because temperature also affects enzyme activity — only pH should change.
How is the optimum pH of amylase identified from the results of the practical?
It is the pH with the shortest time to digest the starch — the peak on a graph of rate against pH.
How do you calculate the rate of an enzyme reaction from the time taken?
e.g. starch is completely digested in 50 seconds- Rate
- per second.
True or false? In the amylase practical, iodine solution is added to the test tube containing the amylase and starch.
False. A drop of the mixture is removed every 30 seconds and added to iodine on a spotting tile (continuous sampling).