An investigation in to the distribution of catalyse in different plant tissues

Photorespiration, Catalase, Hydrogen peroxide

AbstractThis investigation is a study on the distribution of catalyse in different plant tissues. I looked at 7 different tissues and measured the amount of oxygen given off to see the amount of catalyse present. I found varying tissues to have varying amounts present.

IntroductionCatalase is a widespread enzyme, found in nearly all aerobic cells (animals, plants and microbes). It protects the cell from the toxic effects of hydrogen peroxide, generated as a waste by-product of cell metabolism. It does this by catalysing the decomposition of hydrogen peroxide (a powerful and potentially harmful oxidizing agent) into molecular oxygen and water. The reaction can be summarised by the equation:2H 0 2H 0 + 0Different plant materials contain very different amounts of catalase activity and this is what I will be looking at.

Catalase is located in a cell organelle called the peroxisome. Peroxisomes in plant cells are involved in photorespiration (the use of oxygen and production of carbon dioxide) and symbiotic nitrogen fixation (the breaking apart of the nitrogen molecule to reactive nitrogen atoms). Hydrogen peroxide is produced during these chemical processes and must be removed to prevent damage to cellular structures. If hydrogen peroxide is added to tissue containing the enzyme catalyse bubbles are produced, this is evidence of oxygen production and confirms that there was catalyse present.

Catalase has one of the highest turnover rates for all enzymes: one molecule of catalase can convert 6 million molecules of hydrogen peroxide to water and oxygen each minute.

AimsTo investigate the amount of catalyse in varying plant tissuesHypothesisThe more a plant is respiring, the higher the catalyse activity and the more oxygen will be produced.

VariablesThere are many variables, which could affect my results these are:•Temperature- the higher the temperature, the higher the rate of reaction up to a certain point. Whilst the optimum temperature of catalyse is...
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