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Unformatted text preview: Priyal Chitale IB Year 11 Biology SL Dhirubhai Ambani International School BIOLOGY LABORATORY REPORT ANAEROBIC RESPIRATION Aim: To investigate the effect of sugar concentration on the rate of anaerobic respiration of yeast. Introduction: Anaerobic means without oxygen, therefore, anaerobic respiration literally means respiration carried out in the absence of oxygen. A process called glycolysis forms the first step of cell respiration, irrespective of whether it is aerobic or anaerobic it involves the conversion of glucose to pyruvate and the subsequent release of a small amount of ATP or adenosine triphosphate through a chain of cytoplasmic reactions. In anaerobic respiration in humans and some bacteria, anaerobic respiration produces energy and lactate (or lactic acid) in humans, anaerobic respiration cannot be performed for a long period of time, as lactate is toxic and needs to be flushed out of the body fast. However, in yeast, aerobic respiration is not carried out at all, and anaerobic respiration is the usual method of respiration. Yeast is used to refer to a group of eukaryotic micro organisms belonging to the Fungi kingdom when yeast respires, it produces carbon dioxide, ethanol and energy, therefore, anaerobic respiration in yeast is also referred to as fermentation. Both carbon dioxide and ethanol are given out/secreted, as they are toxic to the yeast. Therefore, yeast in used to produce many alcoholic beverages, and is also used to fluff up bread, as the carbon dioxide given out makes the dough rise. The yeast used in this experiment is a form of budding yeast (budding is a type of asexual reproduction) called Saccharomyces cerevisiae , that is widely used in baking and brewing and is known as Bakers yeast. The reaction that describes the anaerobic respiration of yeast is: Pyruvate Ethanol + carbon dioxide + energy CH 3 COCO 2 H C 2 H 6 O + CO 2 + Energy Hypothesis: The relationship between the sugar concentration and the rate of anaerobic respiration of yeast will be directly proportional: The 10 M glucose solution will produce the largest number of carbon dioxide bubbles, and take the shortest time to produce the first bubble. The 1 M glucose solution will produce the smallest number of carbon dioxide 1 Priyal Chitale IB Year 11 Biology SL Dhirubhai Ambani International School bubbles and will take the longest time to produce the first bubble....
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This document was uploaded on 09/08/2009.
- Spring '09