catalase lab intro - norwellschools.org · • purpose of lab: how is catalase enzyme activity...
TRANSCRIPT
Catalase Lab Intro
Check your introduction• Enzyme = Catalase (found in most plants
and animals)• Substrate = H2O2
• Chemical Reaction:
Check your introduction• Why do we have catalase?
Check your introduction• Why do we have catalase?
– Mitochondrial reactions generate H2O2.
Check your introduction• Why do we have catalase?
– Mitochondrial reactions generate H2O2.• By-product of producing energy.• Toxic to cells, so must be broken down.
Check your introduction• Why do we have catalase?
– Mitochondrial reactions generate H2O2.• By-product of producing energy.• Toxic to cells, so must be broken down.
• Why are we using beef liver??
Check your introduction• Why do we have catalase?
– Mitochondrial reactions generate H2O2.• By-product of producing energy.• Toxic to cells, so must be broken down.
• Why are we using beef liver??– Organ that removes toxins.– Contains A LOT of mitochondria.
Check your introduction• Purpose of lab: How is catalase enzyme
activity affected by concentration, temperature, and pH?– Under which condition does catalase work
best???
Hypothesis• Determine your condition. • Create a hypothesis that relates to your
condition. – If…– Then…– Because…
Hypothesis• Determine your condition. • Create a hypothesis that relates to your
condition. – If…– Then…– Because…
• Methods VERY important!
Conduct your experiment• Design--You must show me this before you
begin.
Conduct your experiment• Design--You must show me this before you
begin.– Controlled variables: What will be the same in each
tube?
Conduct your experiment• Design--You must show me this before you
begin.– Controlled variables: What will be the same in each
tube?• Time before measuring; Amt of enzyme & substrate.
Conduct your experiment• Design--You must show me this before you
begin.– Controlled variables: What will be the same in each
tube?• Time before measuring; Amt of enzyme & substrate.
– Independent variable: What will you change and how?
• Don’t know yet.
Conduct your experiment• Design--You must show me this before you
begin.– Dependent variable: What will you measure and
how?
Conduct your experiment• Design--You must show me this before you
begin.– Dependent variable: What will you measure and
how?• Catalase breaks down H2O2 Bubbles!
Conduct your experiment• Design--You must show me this before you
begin.– Dependent variable: What will you measure and
how?• Catalase breaks down H2O2 Bubbles!• Measure rate of production of bubbles in test tube after
H2O2 is added.
Conduct your experiment• Design--You must show me this before you
begin.– Order of addition:
• Enzyme first (bottom of tube).
• Independent variable next.
• Add H2O2 last and measure gas production.
Ways to vary condition?
• Acid/base dropper bottles…how could you vary the pH within your five tubes (and be able to make a line graph)?
• How could you use the freezer or hot bath to get various temperature enzymes and create a line graph?
• How can you change concentration of enzyme or substrate?
• Need FIVE data points for good analysis.
How much enzyme and substrate?
• For enzyme there is a disposable plastic pipette. One pipette is about 1 ml broken into .25 ml gradations
• For substrate there is a measured pipetter. Watch the demo of how it works? How much substrate do you want to put in your tubes? Does it matter?
• Total amount of enzyme and substrate should not exceed 2 ml or your tubes may overflow. Test with your control first!!!
Begin
• BRIEFLY discuss hypothesis.• Design experiment.• Have design checked!!!• Complete lab in lab period,
carefully documenting data and directions.
• Over Week--draft ideas for introduction, hypothesis, and methods; discuss data/graphing!!!