Rate Of Reaction Lab Report

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How Hydrogen Peroxide Affects the Rate of Reaction of the Enzyme Catalase

Introduction:

Catalase, like all enzymes, is made up of protein molecules. It can be found in the cytoplasm of living tissue. It speeds up the decomposition of Hydrogen Peroxide, a metabolic waste product, into water and oxygen that can safely be removed from the cell.

The type of reaction involved is known as a catabolic reaction (i.e. substrate broken down.)This is simply because the substrate enters the active site and is broken down, and leaves as 2 separate products, in this case water and oxygen:

2H2O2> 2H20 + O2

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Like all enzymes, the rate at which the enzyme works is affected by many variables. …show more content…

The maximum produced in my second experiment was 2.6. But this can be explained by how long the enzyme had to react. It takes much longer to reach maximum velocity with a competitive inhibitor present and therefore I believe that if I had left the experiment going the same levels of oxygen would have been produced as in the first experiment. These findings follow my prediction, other than the 90% readings. According to my prediction, even with an inhibitor present the 90% concentration readings should have been higher than the 80% concentration readings. As stated above this could be because that the enzyme concentration is the limiting factor. But the figures actually drop from 80% concentration to 90%. This could be explained because there are so many substrate molecules competing for the active sites of the enzyme molecules that they actually start to block the site. Therefore there is a slight decrease in oxygen produced.

I believe that the inhibitor in the nitrate solution was a competitive one. This because if it was a non-competitive the reaction rate would have risen as concentration rises only for a short while, and then …show more content…

(see evaluation)

Evaluation:

My experiment went very well and I got a good set of results, which I could base my conclusion on.

The accuracy and observations of my experiment, I felt was consistently good. All of my readings were to a degree of accuracy that I felt was adequate. All weight measurements of the celery were 3g, +/- 0.15g. I felt this was accurate enough for my purposes; a size difference of 0.3g at the most would not have made considerable difference. My measurements of oxygen given off were all to 0.1 cc and throughout my experiment I used the most accurate glass measuring cylinder available.

I did not have many anomalous results. But both experiment numbers 2, in the two variable tests (shown in red in the results table) seem to be of a generally lower value than results 1&3. Both these experiments were carried out on the same day. There could have been a number of reasons why these anomalous results occurred:

* My teacher supplied the celery I used for my experiments. It had been purchased from various supermarkets in the area. It

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