Cellular Respiration Essay

791 Words Sep 8th, 2013 4 Pages
The effect of nature of substrates on the rate of cellular respiration in yeast was determined by using the Smith fermentation tube method. Mixtures of 15ml distilled H2O, 10% yeast suspension and 15ml of the following solutions (all at 10% concentration):1- starch, 2 – lactose, 3 – sucrose, 4 – glucose, 5 – fructose, 6 – distilled water , were poured in six smith fermentation tubes. Cotton balls were plugged in the openings of the tubes and the tubes were kept upright and observed for 30 minutes. The mixture with the sucrose solution acquired the highest computed volume of gas evolved and the rate of CO2 evolution seconded by glucose and followed by fructose. This stated that the higher the amount of the CO2 evolved, the faster
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One of these downsides is the formation of lactate in the muscles because of “oxygen debt”, causing it to “burn” and eventually fatigue, until pyruvate is reduced from lactate (Madur, 2009).
Anaerobic respiration can be further divided into two types; namely, alcohol fermentation and lactic acid fermentation. In alcohol fermentation, pyruvate (product of glucose in glycolysis) is converted to 2 molecules of ethanol (C2H5OH) and 2 molecules of carbon dioxide (CO2) while in lactic acid fermentation, pyruvate is reduced directly into lactic acid (Campbell and Reece, 2008). A good example of organism which produces ethyl alcohol and carbon dioxide through the process of alcohol fermentation is yeast (Madur, 2009).
As a unicellular fungus, yeast is also an example of a facultative anaerobe, which depicts an organism with... [continues]


Materials and Methods
In determining the effect of the nature of substrates on rate of cellular respiration, smith fermentation tube method was done. In this method, six smith fermentation tubes were obtained. This special tube has a closed vertical arm which extends into a bulbous portion with tapered opening as seen in Figure 5b. 15 ml of the following solutions, all at 10% concentration, were poured to the respective tubes: 1- starch, 2 – lactose, 3 – sucrose, 4 – glucose, 5 –

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