Investigating Factors Affecting Enzyme Activity.

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Allan Harte – AS Biology                     -  -

Investigating Factors Affecting Enzyme Activity

Investigating Factors Affecting Enzyme Activity.

There are thousands of biological processes and chemical reactions that take place in the body every day, and so the body requires a huge amount of energy to deal with this high demand of activity.  In most cases the energy requirement would be too large, and so cells use enzymes to help with reactions in the body.  Enzymes are a highly renewable source as they do not get used up themselves, meaning that they are biological catalysts, and are highly affective as they greatly reduce the amount of energy needed for a reaction, whilst at the same time making the reaction take place in a shorter space of time.

The liver is a vital organ of the body, and has hundreds of functions.  The typical liver cell contains many organelles called peroxisomes, shown on the right, which oxidise fatty acids and detoxifies alcohol, amongst other processes.  Enzymes in peroxisomes work by transferring a Hydrogen atom from a substrate to an Oxygen atom.  However, although this process is breaking down harmful substances, it also creates H2O2, or hydrogen peroxide, which is a very toxic and dangerous compound, so much so that white blood cells use it in small amounts to kill harmful bacteria.  This byproduct therefore must be removed or it will cause damage to the cell.  The peroxisomes therefore contain another enzyme called catalase, which breaks down the hydrogen peroxide into water and oxygen gas due to this equation:

2H2O2            Catalase          2H2O  +  O2

One molecule of catalase can break down around 6,000,000 molecules of hydrogen peroxide a minute, and the cell can reuse the products of this reaction, which means that this is a very efficient way of reducing waste.

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The most common factors that influence an enzyme’s rate of reaction are pH levels, temperature, and the concentrations of the enzyme and the substrates.  Concerning pH levels, any enzyme will become denatured if its environment differs too greatly from its optimum pH level.  Any enzyme will also become denatured it its surroundings reach a temperature of 40-50°C and above, as body temperature is around 36°C, which, through adaptation, would therefore be an enzyme’s optimum temperature.  An increase in the concentrations of the substrate or the enzyme will expectedly be in direct proportion to the rate of reaction in a ...

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