PAG - measuring enzyme activity

Question 1

how can the progress of enzyme catalysed reactions be investigated

Answer 1

measuring the rate of formation of a product
measuring the rate of disappearance of a substrate

Question 2

method

Answer 2

have varied concentrations of hydrogen peroxide e.g. 2vol - 16 vol increasing in 2vol increments
for each concentration:
measure 50 ml of concentration in a measuring cylinder and pour into a conical flask
using a syringe, measure 1 ml of catalyse enzyme
pour the catalyse into the conical flask and immediately place a bund which is connected using a tube to a gas syringe
start the stopwatch and stop the watch when 80 cm3 of oxygen has been produced
wash conical flask with distilled water
repeat each concentration 3 times and calculate a mean rate at each concentration

Question 3

what is the dependent variables and its issues

Answer 3

DV = volume of oxygen gas produced in a set time
issues
bung not air-tight = some gas escapes
some oxygen dissolves in water / gases other than oxygen also collected
oxygen produces quickly makes accurate measurements of volume difficult
source of enzyme
both mass and surface area of tissue needs to be controlled