|
Enzyme Rate of Reaction
for Catalase |
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Introduction:
Life would not be possible without chemical
reactions. Chemical reactions are responsible for speeding up the process. A
chemical reaction is the process of breaking chemical bonds, forming new bonds
or both. The four things that can speed up a chemical reaction is heat,
increasing the concentration of reactants, decreasing the concentration of
products, and enzymes. Enzyme is a catalase, most the time a protein. Enzymes
can control the rate of a reaction, and they also lower activation energy.
Enzymes are important in regulating chemical pathways, synthesizing materials
needed by cells, releasing energy, and transferring information. Enzymes are
involved in digestion, respiration, vision, movement, and thought. There are
several things that can affect the function of enzymes like temperature, the pH,
and the amount of reactant or product. Simple cells may have as many as 2000
different enzymes, each one catalyzing a different reaction. In this particular
lab, your hands act as the enzyme "Catalase". This enzyme, which is
found in your cells, splits hydrogen peroxide, a byproduct made by your cells
during cellular respiration, into water and oxygen.
Hypothesis:
If time is increased, then more hydrogen
peroxide molecules will be split into water and oxygen
Materials:
The materials used in this lab were pencils,
scissors, envelope, 100 paper hydrogen peroxide molecules, and a watch with a
second hand so that a person would be able to keep time for the person tearing
the strips.
Methods:
Take a paper template and cut out 100 hydrogen
peroxide molecules. Place the cut out pieces into an envelope. Then have a
person act as a catalase and take one piece of the paper molecules out of the
envelope at a time and rip it in two and place the pieces back into the
envelope. Have a person hold the envelope person, while another student keeps
track of the "tearing" time intervals (10, 20, 30 ,60, and 60
seconds). Count how many molecules are ripped at the end of each time
interval and record this number in your data table. When all time intervals and
counts are completed, use the formula below to figure the reaction rate for
catalase. Record this rate in your data table.
M2 - M1 = reaction rate
T2 - T1
Results:
|
Time in seconds |
Ripped Hydrogen Peroxide Molecules |
Rate of reaction |
|
0-10 |
3 |
.3 |
|
10-30 |
10 |
.35 |
|
30-60 |
24 |
.47 |
|
60-120 |
63 |
.65 |
|
120-180 |
124 |
1.02 |
1. What is an enzyme? What are its functions in living
things?
Enzymes are proteins in living systems. Enzymes
can control the rate of a reaction, and they lower activation energy.
2. Name several things things that can affect the
function of an enzyme?
Temperature, the amount of reactant or product
and the pH.
3. Write the chemical equation for the
breakdown of hydrogen peroxide by the enzyme catalase.
hydrogen peroxide + catalase yields water + oxygen
4. An enzyme's efficiency increases with greater
substrate concentration, but only up to a point. Why?
all of the active sites of the enzymes become filled with hydrogen peroxide
molecules
5. If you were allowed to continue this lab and rip
hydrogen peroxide molecules for 240 and 300
seconds. What would happen to the rate of reaction and why would this happen?
It would increase.
6. What can you say about the length of time and the
rate of the reaction?
The less time, the more the reaction rate is
lowered, and the more time, the more the reaction rate is higher.
7. What would happen to the rate of reaction if you
remove the water and oxygen molecules
as soon as they are produced?
It would be faster.
Error Analysis:
All pieces must be returned to the envelope
each time interval to correctly simulate what occurs within a cell.
Discussion and Conclusion:
As the time intervals increased, the reaction
rate of catalase increased also. In a living cell, more hydrogen peroxide would
be broken down by catalase over a longer period of time.