1. E XPERIMENT T IPS

2. We have included in this presentation a few tips on some of the experiments that are on the curriculum. There are more tips to be found on the DVD.

3. 2.2.5 P REPARE AND SHOW THE PRODUCTION OF ALCOHOL BY YEAST. SLSS protocol worked well. Use ethanol to show a positive test result (control) Test after 48 hours. Leave alcohol test overnight for crystals to form. Recommend iodoform test over potassium dichromate. Domestos bleach (thick) as source of sodium hypochlorite. Emphasize anaerobic respiration Positive Results Negative Results

4. P REPARE ONE ENZYME IMMOBILIZATION AND EXAMINE ITS APPLICATION Use Allinsons yeast – no sulfate Use sports drinks bottles with bottom cut off for dropping funnels/bioreactor OR stick straw with holes into dropping funnel OR free in beaker Clinistix (glucose testing strips) cut into 2/3 Keep the beads for alcohol production experiment (Activity Number 12)

5. P REPARE ONE ENZYME IMMOBILIZATION AND EXAMINE ITS APPLICATION o To get perfect beads.  Draw mixture of yeast and sodium alginate solutions into a 20 ml syringe.  Fix syringe into a retort stand 10 cm above the beaker of calcium chloride solution.  Remove the plunger. The contents of the syringe will slowly drop into the calcium chloride solution, forming perfect beads.

6. 2.2.3 I NVESTIGATE THE EFFECT OF P H ON THE RATE OF ONE OF THE FOLLOWING : AMYLASE, PEPSIN OR CATALASE ACTIVITY Use catalase from celery or radish. (Yeast possible but students may mix up with alcohol experiments) Plastic 100ml graduated cylinders Make up fresh enzyme solution with fresh celery Advance prep: to make up buffers – place tablet in water overnight (makes them easier to crush next day)OR crush in mortar and pestle To get pH 14: add a few drops of NaOH solution to buffer pH 10 To get pH 1: add few drops HCl to buffer pH 4 NOTE: optimum pH for celery varies with time of year/temperature from 7 – 9. (Go with majority on the day!)

7. 2.2.3 I NVESTIGATE THE EFFECT OF TEMPERATURE ON THE RATE OF ONE OF THE FOLLOWING : AMYLASE, PEPSIN OR CATALASE ACTIVITY. To ensure the solutions are at the correct temperature leave for at least 15 mins at each temp. before mixing. At the start: set up 2/3 thermostatically controlled water baths at 35 0 C, 45 0 C, 65 0 C; an ice water bath and a tap water temp. water bath Into each water bath place: tube A containing catalase & buffer and tube B containing H 2 O 2 Start with tap water temperature water bath contents: check the temperature of the test tubes. Repeat with other water baths

8. 3.1.4 I NVESTIGATE THE GROWTH OF LEAF YEAST USING AGAR PLATES AND CONTROLS. Do in late September Use older leaves Ash, Beech, Sycamore, Griselinia, Escallonia …all produce good results… Discs/ squares cut from the leaves using cork borers or a sterilised scissors – good mirror images Surfaces can be disinfected using wipes, (Dettol™/Tesco/Johnson and Johnson etc.)

9. 3.5.2 I NVESTIGATE THE EFFECT OF IAA GROWTH REGULATOR ON PLANT TISSUE Use mustard seeds. Grids: Photocopy graph paper onto acetate sheets. Note: MUST be photocopyable acetate or ink will wash off. Rinse, save and store in freezer bags to reuse. Use large round cotton wool pads. Label droppers and petri dishes and arrange paired up for serial dilution. Keep all equipment in a box

10. The End