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Enzyme Activities

Enzyme Activities. Kate Andrews Tricia Geraghty. Simple activities to support the teaching and learning of enzymes at various levels in the curriculum. Background Hydrogen peroxide - a damaging substance produced by living cells.

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Enzyme Activities

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  1. EnzymeActivities Kate Andrews Tricia Geraghty

  2. Simple activities to support the teaching and learning of enzymes at various levels in the curriculum.

  3. Background Hydrogen peroxide - a damaging substance produced by living cells. Cells produce catalase, an enzyme, to remove hydrogen peroxide. Effervescent Enzymes

  4. hydrogen peroxide + catalase  oxygen + water In solution, bubbles of oxygen gas are produced - effervescent enzymes! Catalase speeds up the breakdown of hydrogen peroxide:

  5. To: Identify whether catalase is present in both living and non-living substances Compare catalase activity in a variety of plant and animal tissues Aims of activity 1

  6. Touch a filter paper disc against the freshly cut surface of a non-living substance, plant or animal tissue. Drop disc into a solution of hydrogen peroxide – it should sink If catalase present hydrogen peroxide broken down Oxygen bubbles attach to the disc causing the disc to become buoyant. The process...

  7. Time to float related to how quickly oxygen is produced - hence which tissue contains the most catalase. Comparisons....

  8. Work in pairs. Wear eye protection. Carry out activity 1. Note your results.

  9. To investigate the effect of increasing enzyme concentration on enzyme activity using : - a series of dilutions of yeast cells, or unicellular algae Aims of activity 2

  10. The same as activity 1 except - one drop of each dilution of cells is placed on a filter paper disc. The process….

  11. Some uses of catalase

  12. Protocols adapted from Roger Delpech ‘Microscale Investigations with Catalase’ Ideas for investigations suitable for Advanced Higher projects. http://www.saps.org.uk/attachments/article/293/SAPS%20Student%20Sheet%20-%2024%20-%20Investigations%20with%20Catalase.pdf

  13. An oldie, but a goodie! • Simple activities • Strikingly visual results – easy to record in a variety of ways • Used to develop understanding of enzyme properties • Ideal for discussion of experimental design – variables, controls, conclusions The Breakdown of Starch by Diastase

  14. Based on the action of diastase on starch - diastase starch maltose

  15. The process..... Starch agar well cut in agar with cork borer and filled with diastase Leave set up for 24 hours

  16. What you might see.... Flood the plate with iodine solution and rinse iodine solution becomes blue-black clear area where starch has been broken down

  17. Do barley seeds contain enzymes? diastase solution halved germinating barley seeds germinating barley seeds, halved and boiled

  18. barley grains mashed in water • water as a control

  19. Set up diastase experiments

  20. The problem with lactose.......

  21. Protocol adapted from an NCBE protocol: Better Milk for Cats, (1995)

  22. The Problem with Lactose........ Lactase, a digestive enzyme, speeds up the breakdown of lactose (sometimes called milk sugar) lactase Lactose glucose + galactose

  23. Aims of the activity • To: • To provide a context for developing understanding of enzymes and their uses in industry • To demonstrate a use of ‘immobilised enzymes’ • To provide a context for identifying ‘limitations and improvements......’

  24. The context.... • Cats are fond of milk? • Many cats cannot tolerate cow’s milk - it makes them sick • Pet food manufacturers have produced ‘cat-safe’ milk

  25. A trivial problem?? • Lactose intolerance also affects humans.......... • Lactase is used in the production of lactose-reduced milk for cats and humans who have problems digesting lactose

  26. The process Lactose-reduced milk can be produced in two ways: Lactase can be injected into cartons as UHT milk is being packaged Milk can be treated by enzymes which have been ‘immobilised’ on beads of gel

  27. The process......

  28. Our design

  29. Further discussion In designing a treatment column for the production of lactose-reduced milk, what factors would a manufacturer have to take into consideration?

  30. Further study / investigation

  31. I have taken part in practical activities which involve the use of enzymes and microorganisms to develop my understanding of their properties and their use in industries. SCN 4-13b Curriculum Links

  32. ‘S’ Grade - ..carry out an investigation on the catalase reaction when plant and animal tissues are added to hydrogen peroxide solution. Int 2 - ..demonstrate the breakdown of hydrogen peroxide by heating compared to catalysis with manganese dioxide and catalase. Current ‘H’ Human Biology – Effects of various factors on enzyme activity to include inhibition, substrate and enzyme concentration. Carry out an investigation…..

  33. Biology Unit 2, Human Biology Unit 1: Activation energy experiments, comparing heat, manganese dioxide and catalase action on hydrogen peroxide. Experiments on competitive inhibition. Experiments on reaction rate with increasing substrate concentration. Revised Higher Biology andHigher Human Biology

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