Investigate the effect of the concentration of catalase on the rate of decomposition of hydrogen peroxide

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Zahra Khan- Biology coursework

Biology Coursework:

 Investigate the effect of the concentration of catalase on the rate of decomposition of hydrogen peroxide

Zahra Khan: - 12WS

Centre number: - 51619

Candidate number: - 6547

Introduction

For this investigation I have been asked to investigate (by experimentation) the effect of substrate concentrations on the rate of the decomposition of hydrogen peroxide when catalyzed by the enzyme catalase.  This is part of our work on the function of enzymes, how they work and the effects of conditions on how they work. We have learnt about the formation of enzyme-substrate complexes, the lock and key model, induced fit model, activation energies of normal reactions and enzyme-catalyzed reactions, equilibrium, specificity and denaturisation.

An enzyme (Catalase) is a biological catalyst. It can modify the rate of reaction without being changed itself. Enzymes are also globular proteins that have a three-dimensional specific shape; among with a pocket known as the active site, this has a precise shape to link with the exact substrate. Every enzyme is capable of converting one kind of substrate molecule into one kind of product molecule, which forms the enzyme-substrate complex. However these are the minority factors that can affect the rate of reaction:

Temperature:

If the temperature was to increase so would the rate of reaction up to a decisive point, as the enzyme will start to denature; this usually occurs at temperatures around 50 to 60 Celsius. The rate of reaction increases because enzymes and substrate have more energy permitting them to move around more rapidly, resulting with more collisions and ensuring the enzyme-substrate complex. When the enzymes denature, the weak bonds that hold the tertiary structure of the enzyme together vibrate at an excessive rate, due to the kinetic energy, that they break as well as altering the shape of the active site to a degree that the substrate can no longer link to it.

PH:

The formation of the enzyme-substrate complex relies on an exact complementary shape and charge. If there is a change in pH, it will corrupt the charges so that no enzyme-substrate complex can be formed. All enzymes have an optimum pH depending on where they are based, intracellular or extra cellular.

Substrate concentration:

The higher the concentration that faster the rate of reaction, which is until they are working as fast as they possible can. This increase in rate of reaction occurs because the more substrate there is the more chance there is of collisions resulting in the formation of enzyme-substrate complex. If the reaction is working fast as possible, the limiting factor is no longer the substrate but the enzyme concentration.

Enzyme concentration:

This factor also enhances the rate of reaction because there are a greater number of active sites accessible for the enzyme-substrate complex to be formed.

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Inhibition:

The inhibitor decreases the rate of reaction because it alters the shape of the active site or either blocks the active site so that the enzyme cannot form the enzyme-substrate complex.

I predict with reasons that the more concentration of catalase I use the higher the rate of reaction will be. Reason for this prediction is because every enzyme has a temperature range of optimum activity. Outside that temperature range the enzyme is rendered inactive. This occurs because as the temperature changes enough energy is supplied to break some of the molecular bonds. When these forces are disturbed and changed ...

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