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Action of catalase and MnO2 on hydrogen peroxide

  1. Jul 12, 2004 #1
    can anyone give some comments or inferential analysis to the research presented below? thank you :D some info and answers to the topic questions would be nice to hear too!

    "To compare the action of catalase and manganese dioxide on hydrogen peroxide."

    1. Label 4 test-tubes A, B, C and D.
    2. To each tube add 5cm3 of hydrogen peroxide.
    3. Prepare the contents of the 4 tubes as shown in the table below. For each tube record the observations. Test any gas given off with a glowing splinter.


    A. 5cm3 hydrogen peroxide solution + 1 small pieace of fresh liver

    B. 5cm3 hydrogen peroxide solution + 1 small piece of boiled liver (Boil the liver for 10 minutes and cool before use.)

    C. 5cm3 hydrogen peroxide + a little manganese (IV) oxide

    D. 5cm3 hydrogen peroxide solution + a little boiled manganese dioxode (The manganese dioxide has been boiled and cooled before use.)

    4. What type of substance is in the liver which could bring about the reaction in tube A?

    5. How do you account for your observation in tube B?

    6. From your observation on D, what can you conclude about manganese (IV) oxide?

    7.Repeat experiments A and B using a piece of potato tuber.

  2. jcsd
  3. Jul 12, 2004 #2


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    What enzyme is present in the liver? It is clearly stated in you title.

    The reaction should be negative.
    What happen to proteins when you heat it up? What would be the effect on an enzyme? Therefore the enzyme is heat stable or labile?

    Manganese dioxide is an inorganic catalyst (but not an enzyme) for the breaking down of hydrogen peroxide. Reaction C & D have the same reaction. Therefore manganese oxide is the opposite of catalase

    It should give the same reaction as with the liver piece. Why? same enzyme is present in the potato.

  4. Jul 12, 2004 #3


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    Have you performed this experiment yet? You didn't show your data.
  5. Jul 13, 2004 #4
    nope we didn't do it yet...
  6. Jul 13, 2004 #5


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    Did your manual or instructor specify that catalase in present in both the liver and in potato tubers? If not, ian probably shouldn't have given that away. Have you learned yet about the effects of temperature on the activity of enzymes and on inorganic catalysts? I'm going to assume you have, but if not, ian kind of gave that one away as well. Just to reiterate the point, boiling the liver will denature the enzyme (as it would any protein), and without the proper conformation for its active site, the enzyme will cease to function. Boiling the manganese dioxide, on the other hand, will have no effect and that reaction should proceed as if you had never boiled the catalyst.

    I believe you are breaking down hydrogen peroxide into water and elemental oxygen, so that positive reactions will give off oxygen gas, which will ignite your glowing splinter. In short, the splinter should light up when placed over tubes A, C, and D, but not when placed over tube B. Now, just to review, can you tell me why this is and give your expected answers for questions 4 -7 (without directly quoting ian or myself)?
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