biological molecule Optional: if using saliva – (each cloth should have hypochlorite (bleach) solution the same range of or 1% Virkon solution for stains, and there should disinfection of equipment and be one cloth for each benches, small beaker or type of enzyme to be other container for collecting used), range of saliva. enzymes that have different substrates Digital resource: Enzymes animation B1g Enzymes B1.9 Explain the effects of 1) Cut an apple or pear This practical investigates the Use a suitable enzyme activity temperature, substrate in half (slices of celeriac effect of pH on amylase, the and substrate such as concentration and pH on also work well), and enzyme that catalyses the using catalase/hydrogen enzyme activity sprinkle lemon juice over breakdown of starch to smaller peroxide and measure the cut surface of one sugar molecules. The iodine the volume of oxygen half. Explain that cutting test identifies the presence of collected every 30 s for Demonstrate an B1.11 the fruit breaks open starch, but does not react with 5 minutes. Measure and understanding of rate cells, releasing enzymes sugar molecules record the pH of the calculations for enzyme that were inside. Ask enzyme/substrate activity students to describe the solution at the start of The optimum pH for human changes they see the experiment.Record salivary amylase is pH7. Other Investigate the factors that B1.10 happening, and try to the cumulative gas amylases may vary from this affect enzyme activity suggest a reason for any volume over time, and value, but there should be one differences between the plot the values on a pH that clearly allows greater two halves graph of gas volume enzyme activity than the against time others. 2) Ask how you would tell from the results of Students should make Equipment: For each pH two experiments using the link between the tested: test tube containing 5
Optional: if using saliva – hypochlorite (bleach) solution or 1% Virkon solution for disinfection of equipment and benches, small beaker or other container for collecting saliva. biological molecule (each cloth should have the same range of stains, and there should be one cloth for each type of enzyme to be used), range of enzymes that have different substrates Digital resource: Enzymes animation B1g Enzymes activity B1.9 B1.11 B1.10 Explain the effects of temperature, substrate concentration and pH on enzyme activity Demonstrate an understanding of rate calculations for enzyme activity Investigate the factors that affect enzyme activity 1) Cut an apple or pear in half (slices of celeriac also work well), and sprinkle lemon juice over the cut surface of one half. Explain that cutting the fruit breaks open cells, releasing enzymes that were inside. Ask students to describe the changes they see happening, and try to suggest a reason for any differences between the two halves 2) Ask how you would tell from the results of two experiments using This practical investigates the effect of pH on amylase, the enzyme that catalyses the breakdown of starch to smaller sugar molecules. The iodine test identifies the presence of starch, but does not react with sugar molecules The optimum pH for human salivary amylase is pH7. Other amylases may vary from this value, but there should be one pH that clearly allows greater enzyme activity than the others. Equipment: For each pH tested: test tube containing 5 Use a suitable enzyme and substrate such as using catalase/hydrogen peroxide and measure the volume of oxygen collected every 30 s for 5 minutes. Measure and record the pH of the enzyme/substrate solution at the start of the experiment.Record the cumulative gas volume over time, and plot the values on a graph of gas volume against time Students should make the link between the
GCSE9-1ScienceTerm1detailedplanning-UPDATE1.docx