Effect of different size beads on the activity of immobilised catalyse

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Effect of different size beads on the activity of immobilised catalyse Aim: To find out how varying the size of beads containing yeast varies the rate of activity of catalase in a fermentation reaction of hydrogen peroxide with immobilised enzymes. A catalyst is a substance that speeds up the rate of a chemical reaction, without itself being used up in the process however it maybe affected physically i.e. degradation of the surface of the catalyst. Catalysts work by reducing the activation energy needed for a particular reaction by offering a different path for the reaction to take place. Activation energy is the energy, which needs to be supplied before a reaction can occur, basically the amount of energy needed to overcome the bonds between the molecules and atoms. [IMAGE] Catalysts are usually specific to one reaction, that is, different reactions need different catalysts. This is the lock and key theory however there is another theory as well called the induced fit theory. Since a catalyst is not used up during a chemical reaction, it can be used over and over again to convert reactants to products. In this experiment I will be using the immobilised enzyme yeast. When an enzyme is immobilised in this case it is encapsulated in a sodium alginate gel. When an enzyme is immobilised it is in a more stable state, they are better able to resist alteration to shape and activity. In particular they are less likely to be inactive or denatured by changes in pH, presence of other chemicals, or high temperatures. Immobilised enzymes can also be used for longer periods before their activity reduces which is useful in the experimen... ... middle of paper ... ...might have a larger surface area to volume ratio however the bead might be so big that there might be more enzymes on the outer surface. Percentage errors I can work out the percentage errors for my measurements, by using this formula. Mass of calcium chloride (0.005 x 100)/1.4 = 0.7% Mass of sodium alginate (0.005 x 100)/0.4 = 0.2% Pipette (0.05cm3 x 100)/10=5% (0.05cm3 x 100)/5=2.5% (0.05cm3 x 100)/15=7.55% (0.05cm3 x 100)/2=1% (0.05cm3 x 100)/50=25% Measuring beaker (0.2 cm3 x 100)/250 =0.08% Measuring tube (0.1 cm3 x 100)/10 =1% Measuring tube containing hydrogen peroxide (0.1cm3 x 100)/50 =0.2% Measuring tube containing water (0.1cm3 x 100)/100 =0.1% Measuring tube to calculate volume of beads (1cm3 x 100)/8 =12.5%

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