Core Practical: Enzymes & pH Flashcards
All 4 cards in this deck
What are the steps to investigate the effect of pH on amylase activity?
e.g. using starch solution, amylase and iodine- Mix starch solution, amylase and a pH buffer solution in a test tube.
- Every 30 seconds, put a drop on a spotting tile and add iodine solution.
- Record the time for the iodine to stay orange-brown (all starch digested); repeat at different pH values.
What colour is iodine solution when starch is present, and when it is not?
Blue-black when starch is present; orange-brown when no starch is present.
Give three variables that must be controlled when investigating the effect of pH on amylase activity.
Temperature; volume and concentration of amylase; volume and concentration of starch. (Also the size of the test tube.)
Give two improvements that would help find an enzyme's optimum pH more precisely.
Use smaller intervals of pH around the optimum; repeat each pH and calculate a mean. (Also use a water bath to control temperature.)