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A level biology required practical method Watch

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Size:  517.7 KBThis is the require for practical that we are going to be carrying out on Tuesday and we have to plan a method for how we are going to do it using this apparatus.
    I've looked online for help on what to do during the experiment but I haven't found anything that uses this apparatus?? Please help

    The fermentation reaction gives out CO2, which is of course a gas so you can measure its volume.

    HYPOTHESIS: THe prediction is that different substrates will result in different rates of respiration of the yeast, with glucose resulting in the fastest rate. This prediction would be based on the fact that glucose is a monosaccharide so does not need to be digested first (unlike sucrose and lactose which are disaccharides). Fructose would need to go through the hexose monophosphate shunt, which is also slower.

    METHOD: PLace equal quantities of yeast in the syringes, and connect the capillary tubes; then place a short length of water in the capillary. When the yeast respires (apply warmth to allow this to happen) the CO2 released will push the level of water in the capillary tube upwards. Your plan would be to measure the distance of this movement per time. Repeat with each substrate turn by turn and record your results.

    RESULTS: Draw a table with the four substrates as column headings (Five columns); first column will have row headings (1, 2, 3 etc depending on how many separate measurements you do for each substrate). The values in the table could be mm s^-1. Repeat a few times to get an average so results are more reliable. Keep temp constant.
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