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Activity of the Enzyme Catalase with Hydrogen Peroxide.

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Activity of the Enzyme Catalase with Hydrogen Peroxide Background Information: 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 are capable of converting one kind of substrate molecule into one kind of product molecule, which forms the enzyme-substrate complex. There are the minority factors that affect the rate of reaction that include: 1. 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. 2. 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 extracellular. ...read more.


Preparation of the concentrations: When adding my potato tissue with different concentrations, I will have to combine them in the following ways four times: 100% - 20ml Hydrogen Peroxide 0ml Distilled water 75% - 15ml Hydrogen Peroxide 5ml Distilled water 50% - 10ml Hydrogen Peroxide 10ml Distilled water 25% - 5ml Hydrogen Peroxide 15ml Distilled water 0% - 0ml Hydrogen Peroxide 20ml Distilled water Equation: 2H2O0 2H20+O2 Hydrogen Peroxide (Substrate) Water + Oxygen (Products) Variables: Dependent variable - Oxygen Produced Continuo's variable - Concentration of substrate Fair testing: Fair testing allows the experiment to be conducted moderately and giving you accurate results, the following list is of all the fair testing aspects that I will cover: 1. Making sure that I weigh 2.0g of potato tissue after it has been homogenised accurately. 2. Macerate the potato tissue in a homogeniser to assure that the surface area is kept comparable. 3. Making use of the buffer tablets so that the pH is kept constant. 4. Accurately measuring out 20ml of hydrogen peroxide and distilled water, as well as pouring out all 100ml of the mixtures. 5. Drying the inside of the glass syringe is important, as it may be moist and then closing the syringe entirely. Also the rubber pipe must be all open and the rubber bung must be in reach inside 2 seconds, so there is no excess of gas escaped. 6. Making sure that the stopwatch is on 0 seconds and using the correct time and I will do this by asking someone to remind me when 20 seconds have elapsed. ...read more.


This is what I expected before I started the experiment and it also shows I carried it out correctly. Trail experiment Experiment 1 Experiment 2 Experiment 3 Overall Averages Average Gas Produced (Trail Experiment) Average Gas Developed (Experiment 1) Average Gas Developed (Experiment 2) Average Gas Developed (Experiment 3) Average Gas Produced (Overall) Evaluation: The results obtained from the experiment shows that as substrate concentration increases so does the rate of reaction, yet there are many aspect that may result in more accurate results. This may include the temperature, apparatus, different potatoes, etc. If I were to do the experiment again in the future, I would take some further factors into consideration, such as: 1. I would attempt to keep the temperature more constant. This is because the room temperature may have varied and could have had an effect on the results. 2. I may perhaps use a wider range of concentrations to acquire a wider range of results to investigate and compare. 3. Maybe I'd use smaller flasks because this could have an effect on the amount of collisions that occur and the rate of reaction would possibly increase. 4. Perhaps I could use a technique of reducing the amount of gas escaping from the syringe because I assume that some may have escaped. 5. I could use a gas syringe with a glass pipe, as an alternative instead of the rubber pipe, as some gas may have been lost through it. 6. Maybe to use more potatoes in grams because it could increase the amount of gas produced and are more apt. AS Biology Coursework Jagjit Johal ...read more.

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