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Investigating the affect of soaking on catalase activity in red kidney beans

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Introduction

Investigating the affect of soaking on catalase activity in red kidney beans. Aim To demonstrate that the kidney beans have catalase activity and that this activity is dependent on water. Prediction I think the catalase activity will increase and produce more oxygen the longer the kidney beans are soaked. There will come a point where water will not affect the rate of reaction. the oxygen produced will stay constant from this point on. Fair test In order to make this a fair test I have to make sure that all variables are controlled. The kidney beans must be of identical mass. The pH has to be controlled The same goes for hydrogen peroxide (substrate) concentration. This is because concentration of enzyme and substrate affects metabolic activity. The pH will be kept constant by using a pH 7 buffer. The temperature must also be kept constant for the same reason. The volume of water needed for soaking will also be kept the same. This will ensure fair soaking. Lastly, the timing will be constant. I will measure the volume of water produced for each experiment after 2 minutes. If these variables were not kept constant the results cannot be compared accurately. ...read more.

Middle

When the pH is increased the enzyme will loose positive H ions, and in turn, will eventually loose its shape. In both cases the substrate will not fit the active site of the enzyme. The enzyme will be denatured and it will not carry out its job. * Temperature An increase in temperature effects the rate of reaction in two ways. 1. Collision theory - When heat energy is increased, the kinetic energy also increases. This causes the substrate and enzyme molecules to move faster causing more successful collisions. The more often they collide the greater the rate of reaction. 2. Increasing the temperature can, on the other hand, denature the enzyme (enzyme looses its catalytic features). When enough heat is added the molecules start to vibrate. As the vibrations increase it starts to break hydrogen bonds, ionic bonds, hydrophilic bonds, hydrophobic bonds, etc. this causes the 3D shape to change. The substrate can no longer fit into the active site. The catalytic properties have now been lost. The actual affect of temperature combines these two properties to reach an optimum temperature. ...read more.

Conclusion

* Once the soaking was complete the contents was filtered so that the water could be extracted. * Once the beans were ready I opened up the filter paper and scooped up the contents, carefully, with a spatula. I put the beans into the test tube containing the pH 7 buffer and 2H2O2, and followed the same steps as stated earlier. Variables kept constant: * 2g of kidney beans * 10cm cubed of water for soaking * Temperature of 2H2O2 * 10cm cubed of H2O2 * 2cm cubed of pH 7 buffer solution * timing kept at 2 minutes for each experiment Variables not kept constant: * Length of soaking Development of Prediction My prediction states that water is needed for catalase activity to take place. The reaction is dependent on water. A mature seed contains 10% water. This explains the decomposition of 2H2O2 when it goes through no soaking at all. The seed at this point (no soaking) is very stable and activity will surely increase as more water is added. The seed structure determines what goes in and out of the kidney bean has a protective layer called a testa. The catalase exists within the testa. The catalase can only be activated when the testa breaks apart. Metabolic activity occurs in the embryo Zaineb Sheikh (HPE) ...read more.

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