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Unit 1: Microscopy

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Unit 1: Microscopy Chemical or Equipment Methylene blue Conical Glass Water bath Lamp Slide Pipette Hazard Could stain Could shatter Could burn Could burn Could shatter Could use too much substance Nature of Risk Could stain clothes Could cut skin Could burn skin Could burn skin Could cut skin Could jeopardise experiment Minimise Risk Wear protective clothing Be careful Do not touch water bath Do not touch the light bulb Handle with care Handle with care and accuracy Emergency Procedure Wash immediately Tell the teacher Run under cold water Put under cold water Tell teacher. Seek first aid Tell teacher, clean up excess Disposal Wash off Put in glass bin No disposal No disposal Put in glass bin Put in bin Risk Assessment Apparatus Apparatus Reason Microscope To view the yeast cells and carry out the experiment Pipette To apply methylene blue to the side, so that the yeast cells can be differentiated Slide To add yeast cells to, so they can be viewed under the microscope Cover slip To prepare the sample so that the sample is kept in place Lamp To add light, so that the yeast cells can be ...read more.


15 7 12 13.1 Sample B- 37�C Group number 1 2 3 4 5 6 7 8 9 10 Mean Clear 11 16 8 8 13 5 15 15 7 10 10.8 Blue 1 1 2 2 3 6 1 1 0 3 2 Total 12 17 10 10 16 11 16 16 7 13 12.8 Sample C- 45�C Group number 1 2 3 4 5 6 7 8 9 10 Mean Clear 4 4 3 2 2 2 4 2 2 4 2.9 Blue 8 13 7 10 14 13 12 13 5 8 10.3 Total 12 17 10 12 16 15 16 15 7 12 13.2 Conclusion When I had documented my results, I decided that I would use the mean of each set of results collected. This was to make the results more fair and accurate, as doing this would reduce the effect of any outliers in the results. The following results are that of the percentage of viable yeast cells using the mean results for each sample: The equation used to work out each percentage was: Mean number of clear x 100 = --% Mean number of total Sample ...read more.


The equation for anaerobic respiration is: glucose ethanol + carbon dioxide The balance equation is: glucose 2 carbon dioxide + 2 ethanol And the symbol equation: C6H12O6 2CO2 + 2CH3-CH2-OH Evaluation Several problems occurred when preparing the slide and counting the cells. First of all, I added too much of the dye, methylene blue, to the yeast culture. This made the yeast cells difficult to count due to the fact that, when it was viewed through the microscope, the whole slide appeared very blue. Also, when the cover slide was placed onto the slide, a large amount of the culture was pushed to the sides of the slide. This may have affected my counting and results, due to the fact the cell location was different and unviewable. If I was to do the whole investigation again, I would make changes to the experiment. I would make sure less dye was added to the culture. This will prevent the cover slide from sliding off the slide and making the culture easier to view. Also, with less dye, no cells will be pushed out of the cover slide, so there will be more cells to count. ?? ?? ?? ?? ...read more.

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