resent different concentrations.) The control group consists of: 0% test tube, which does not contain ethanol and the control tube containing all but the yeast suspension. Then, we pre-incubated all the test tubes at 30 degrees followed by filling each of the test tubes with 2 ml of yeast suspension. Durham tubes were filled with the water, yeast, sugar, and ethanol solution from the tubes and than inverted back into the test tubes. Next, we measured the volume (ml) of solution remaining in the Durham tube for 45 minutes in 5 min. intervals. (Biology 107 lab manual, 2002)
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