AS Biology Coursework - Enzymes

This is for my Mock Coursework/Pratical exam

Brief: "You are required to plan an investigation into the effect of substrate concentration on the activity of the enzyme catalase. Living yeast is a rich source of the enzyme catalase"

You are provided with a 10 volume (1.0 mol dm(-3)) of hydrogen peroxide - I know to get different concentrations of the hydrogen peroxide I have to water down the concentration.

Could anyone help me out with:

1. I know I need to measure the volume of gas produced in a set time - could anyone suggest a time? I'm not sure on how slowly/quickly this reaction takes place

2. Since I'm starting of with a 1.0mol dm(-3) concentration, and watering it down, will this starting concentration be enough to achieve V(max) on a substrate concentration/initial rate of reaction graph?

3. How many concentrations should I use? I was thinking on 1.0, 0.75, 0.5, 0.25 - since it would be enough to plot a line graph - the only problem is that I have to carry out this plan when I'm at school, and I know I'll have to repeat each concentration for accuracy.

I'd appreciate any help anyone can offer

[I know I've included a lot of detail, but I read a thread a while back saying how it's irritating to ask for help n c/w and not give many details]

1) the slowest it took for me was about 2-3 minutes for the weakest solution.

2) No, initial rate connot be gotten with the equipment you have. It is a limitation to be written up.

3) Maybe a bit more concentrations.

Thanks very much for the help 2776