Enzymes:
Catalase in Animal and Plant Tissues
Sarah Billingsley
Sarah_michelle1993@hotmail.com
Biology 1730.508
October 9, 2012
Vrinda Kulkarni
Tuesday 8am
Absract:
In this experiment, we were determining the breakdown of hydrogen peroxide in cells.
Our hypothesis stated that, “The breakdown of hydrogen peroxide occurs at the same rate in all
cells”. We were testing whether or not the catalase works just as fast in one type of cell as it does
in another. We used all living organisms for this experiment (plant and animal cells). In
performing this experiment we used 4 test tubes and put 1 ml of water in each. We then added
tissues of apple into the first, potato in the second, chicken breast in the third, and beef liver into
the fourth. After this we added 1 ml of hydrogen peroxide into each tube and, after 1 minute,
measured the thickness of the foam in each tube.
Introduction:
A catalyst speeds up the rate of chemical reactions. An Enzyme is an organic catalyst. It
speeds up the rate of chemical reactions in living organisms only. Without enzymes, chemical
reactions within the cell would not be able to happen fast enough to support life. Enzymes lower
the amount of activation energy needed for the reaction to start. Amino acids determine the 3-D
structure of an enzyme which allows it to fit into a certain substrate molecule. The enzyme will
mix with a substrate molecule to make an enzyme-substrate complex and creates a product
molecule that will separate itself from the enzyme which then becomes recycled. Hydrogen
peroxide can damage a cell badly. A catalase breaks down hydrogen peroxide so that it does not
damage the cell.
Materials and Methods:
We took extracts of tissues from an apple, potato, chicken liver, and beef liver and mixed it with
1 ml of water into 4 separate test tubes. Then we added 1 dropper of hydrogen peroxide to each
test tube and waited 1 minute to see the reaction. After the minute was up, we recorded the
thickness of the foam layer (in mm) in each of the test tubes. Our results are illustrated in the
table below:
TUBE
THICKNESS OF
TUBE
FOAM LAYER
1. Apple
0
THICKNESS OF
FOAM LAYER
mm
3.
Chicken
1 mm
Breast
2. Potato
9mm
4.
Beef Liver
64 mm
Results:
Our results proved our hypothesis wrong. The catalase broke down different amounts of the
hydrogen peroxide within the given 1 minute. The apple extract showed 0 mm of foam, the
potato had 9mm of foam, the chicken breast had 1mm of foam, and the beef liver had 64 mm of
foam. This shows that the catalase works at different speeds in different types of cells.
Discussion:
To conclude this experiment, I must note that it is most likely the size of the organism
that determines how fast the catalase works. It probably has to do with the fact that the larger
organism has more enzymes to speed up the process. The chicken and liver were larger and are
therefor, most likely the reason for more foam created. However, it does not make sense to me
that the chicken breast has a smaller foam layer than the potato. If the chicken is larger, the
catalase should be able to work faster to keep the cells from becoming too badly damaged.
Works Cited
Reece, Jane., et al. Campbell Biology., 9th ed. San Francisco: Campbell, 2011,2005. Print.