The effect of enzyme concentration on the rate of reaction of the enzyme catalase.

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Farah Aslam

Biology Practical Assessment:

The effect of enzyme concentration on the rate of reaction of the enzyme catalase.

Skill G: Interpretation of Results

Table of class results to show the effect of catalase concentration on the rate at which oxygen gas is released.

*The mean volumes were rounded to whole figures as the measuring cylinder measured to the nearest cm3

Anomalous results

Trends and Patterns

The general trend of the graph shows that as the concentration of catalase increases, the rate at which the oxygen is produced increases. At a concentration of 20% catalase, the rate is 9 cm3 min-1, and this increases to 26 cm3 min-1 at 60%, before increasing further to 39 cm3 min-1 when the catalase concentration is at 100%.

Conclusion.

As the concentration of enzyme-catalase- increases, the rate of reaction increases, therefore more oxygen gas is produced at a quicker rate.

Discussion

Enzymes are globular proteins and have a specific tertiary structure determines by the arrangements of the amino acids and the ionic and hydrogen bonds present. Due to this specific structure, enzymes can only bind to specific substrates and this binding occurs at the active site. Once an enzyme has bound to its substrate, an enzyme-substrate complex is formed, after which the enzyme is released along with the new product.

There are two hypotheses concerning the production of enzyme-substrate complexes: induced fit and lock and key. The latter suggests that the enzyme and substrate must have complementary shapes to each other where the substrate fits exactly into the active site.

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The induced fit theory suggests that enzymes have some flexibility and that once the enzyme and substrate are bound; the enzyme alters shape to accommodate the substrate.

In this investigation, the enzyme, or catalase, concentration was the independent variable whereas the substrate concentration- hydrogen peroxide- remained the same throughout. The rate of an enzyme controlled reaction is always proportional to the enzyme concentration and this is supported by the graph ...

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