Catalase Lab Experiment

How do enzymes work?

Pre-Lab Questions What is an enzyme? What is a catalyst?

Enzyme - a protein that breaks down or creates molecules. Catalyst - speed up chemical reactions

Connections: enzymes can act as catalysts to help break down or create molecules, thus speeding chemical reactions up!

What is the job of catalase in living cells? Catalase breaks down hydrogen peroxide to avoid cell

damage. (hydrogen peroxide is a by-product of cellular

respiration) (cell respiration - how cells make energy from glucose)

What is it advantageous to use enzymes in chemical reactions? Most cell functions involve chemical reactions, enzymes

will help speed those reactions along.

Pre-Lab Questions

What is a good hypothesis for this experiment? If the enzyme catalase is exposed to heat then it will not

speed help hydrogen peroxide breakdown. If material containing enzymes has more surface area then

more enzymes interact with substrates resulting in a faster reaction rate.

What is the independent and dependent variables? IV: Heat or Increased surface area (for the first and

second hypothesis, respectively) DV: Reaction Rate

For the Lab report, let’s go with the HEAT based hypothesis, while still observing the other factors.

V. Questions What is the substrate in this lab?

The substrate was hydrogen peroxide. What evidence showed that catalase in the

liver was working? (Answers vary…) The bubbling and frothing, and

warmth.

Which sample had the fastest reaction rate? The ground up sample.

Which sample had the slowest reaction rate, or none at all? The cooked sample.

V. Questions Why was there a different reaction rate between

Sample 1 and 2? Sample 1 reacted quickly, but Sample 2 did not react

because the enzymes were denatured, meaning they don’t work.

Why was there a different reaction rate between Sample 1 and Sample 3? More enzymes could come into contact with the substrates in

Sample 3 allowing for a faster reaction rate.

Was there a sample that changed temperature during the reaction? If so, why did this occur? Sample 1 and 3 should have felt somewhat warm. This is

because chemical reactions often give off energy in the form of heat.

How did the surface area impact the reaction rate… A high surface area means there is more enzyme exposed to

interact with the substrate, therefore a fast reaction rate was observed.