View source for GCSE Biology Required Practical: Enzyme Rates of Reaction

==Key Stage 4==
{{#ev:youtube|https://www.youtube.com/watch?v=8Yqbu56ImXk}}
===Meaning===
Investigate the effect of [[pH]] on the rate of reaction for an [[enzyme]].

===Experiment Version 1===
====Variables====
*[[Independent Variable]] - [[pH]] of the buffered [[pH]] [[solution]].
*[[Dependent Variable]] - Time taken for the colour change to take place.
*[[Control Variable]]s - The temperature of all solutions. The volume of all solutions.
====Method====
#Place [[Test Tube|test tubes]] containing a range of of [[pH]] [[Buffer Solution|buffer solutions]], a container of [[starch]] [[solution]] and a container of [[amylase]] [[solution]] in a water bath at a [[temperature]] of around  30°C and wait until all [[solution]]s reach that [[temperature]].
#Use a [[pipette]] to place one drop of [[Iodine Solution]] into each depression in a [[Spotting Tile|spotting tile]].
#Use a clean [[pipette]] or [[syringe]] to place 2cm<sup>3</sup> of each [[pH]] buffer into a [[Test Tube|test tube]].
#Use a clean [[pipette]] or [[syringe]] to place 2cm<sup>3</sup> of starch solution into the same [[Test Tube|test tube]].
#Use a clean [[pipette]] or [[syringe]] to place 1cm<sup>3</sup> of [[amylase]] [[solution]] into the same [[Test Tube|test tube]] and start the [[stopwatch]].
#Use a clean [[pipette]] to remove a drop of the [[solution]] form the [[Test Tube|test tube]] and drop it on the spotting tile every 10 seconds, beginning at 0 seconds.
#Repeat this until the [[Iodine Solution|iodine solution]] in one of the depressions no longer turns black, but instead remains orange.
#Repeat steps 2 to 7 until all different [[pH]] buffers have been tested.
#Plot a graph with [[pH]] on the x-axis and time taken on the y-axis.