"An investigation into the Respiration of Carbohydrate Substrates by Yeast."

... AS Biology Coursework 2004. Lucy Nuttney "An investigation into the Respiration of Carbohydrate Substrates by Yeast." Abstract. The investigation considered the reactivity of respiration of three different carbohydrate substrates; glucose, sucrose and starch, by two different sub-species of saccharomyces cerevisiae yeast. The rate of reaction was measured by collecting volumes of gas in a displacement reaction at standardised conditions e.g. time, temperature, pressure, volume of yeast/ sugar. Results showed that glucose produced the most carbon dioxide, followed by sucrose then starch, the biggest difference being between sucrose and starch. Baker's yeast had a slightly higher average than brewer's yeast but it was not considered to be a significant difference and therefore could have been due to chance. It was concluded that both yeasts respire glucose and sucrose at insignificantly different rates but the difference between starch is much larger and therefore much more significant. Pilot Experiment. Before we could test which carbohydrate and type of

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