1. Catalase Lab Experiment How do enzymes work?

2. 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.

3. 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.

4. 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.

5. 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.