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An investigation to compare the reaction rates between potato and hydrogen peroxide against liver and hydrogen peroxide through loss in mass.

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Introduction

An investigation to compare the reaction rates between potato and hydrogen peroxide against liver and hydrogen peroxide through loss in mass. Background information: Catalase is an enzyme that is found in all cells. This means that it is an intracellular enzyme. And enzyme is a biological catalyst. A catalyst is some thing that speeds up a reaction without being changed itself. Because of this enzymes and catalysts can be used again and again. Enzymes are protein chains that have a primary, secondary and tertiary structure. Their primary structure shows the order and types of amino acids used to form the protein chain. The secondary structure shows the basic folding of the protein and is held in place by hydrogen bonds. The tertiary structure shows a more complex folding which gives it its globular shape. The tertiary folding of the enzyme also gives it its active site. The active sit of an enzyme is the part of the enzyme that determines what the enzyme will react with. If this active site is destroyed in any way the enzyme is said to be denatured and will no longer work. Certain things affect the reaction rate of a substance where an enzyme is used. The concentration of the reactant will affect the reaction rate. If there is a strong concentration of reactant or catalase then there will be a faster reaction rate than if the concentration was weak. ...read more.

Middle

The reaction was quite slow but measurable so I decided to continue with these amounts for my real investigation. I also found out that the potato reaction starts to stop after three minutes so I decided to record the mass every 20 seconds for three minutes. Method: First of all I weighed out 2g of the internal tissue of a potato on and 2g of liver on the top pan scales. Then using the pestle and mortar I separately crushed up the two reactants. To help crush the liver a pinch of sand was placed in the mortar. Then I measured out 20 ml of hydrogen peroxide and diluted it with 20 ml of water making a 50% concentration solution of hydrogen peroxide. Next I placed my 500 ml beaker on the top pan scales and returned the weight to zero. After adding my potato to the beaker I added the hydrogen peroxide and recorded the weight in my table. Every 20 seconds after this I recorded the weight on the top pan scale. I continued to take readings for three minutes aggravating the solution after every reading. After three minutes was over I repeated the experiment keeping everything the same except this time I used 2g of crushed liver instead of potato. Once this experiment was over I repeated the potato experiment and then I repeated the liver experiment. ...read more.

Conclusion

This could've been for a number of reasons. For instance because I was using very delicate measuring scales a little disturbance in the air could've changed my results. Also because after every 20 seconds I was agitating the reactants and placing the beaker on the scales I could've placed it in a different place each time and this would've changed my results. Or when I was agitating the reactants I could agate it more sometimes and this would've caused a faster reaction. I think that my experiment was very valid. This is because it gave the expected results. If my results had not shown what was expected then, I would've redone my experiment to find out where I went wrong. If I were to do the experiment again I would try to do it in a place with less people. This is because whilst I was doing my experiment there were a lot of people walking around. This caused a draft around my experiment and it changed my results. I would also repeat my experiment more so that I could get a more accurate result. I would take this experiment further by finding out if other organisms held more catalase. For instance I could see if the potato skin had more catalase in them then potato flesh does. I could also find out if kidneys had a faster reaction rate than liver. I would do the same experiment using the same measurements but I would use a wider variation of reactants. ...read more.

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