The Effect on the Rate of Respiration of Yeast Cells with Glucose when the Temperature is Varied

4659 Words Jun 17th, 2018 19 Pages
The Effect on the Rate of Respiration of Yeast Cells with Glucose when the Temperature is Varied


The aim of the experiment is to investigate the effect of temperature on the rate of respiration of yeast cells with glucose. As yeast cells use up glucose in respiration, carbon dioxide gas is given off. Measurements of the volume of carbon dioxide gas given off within a set amount of time can be used to measure the rate of reaction. A fast rate of reaction would be indicated by a large volume of carbon dioxide gas being collected within this set amount of time. A small volume of carbon dioxide gas collected within the same amount of time would indicate a slower rate of reaction. The rate of
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As the yeast cells begin to take up the glucose in solution during the first few stages of the experiment, they respire aerobically:

[IMAGE]Glucose + oxygen carbon dioxide + water + energy ==================================================================

Glycolysis takes place in the cytoplasm, whereby glucose is converted to pyruvic acid. Oxygen is present at this stage and the pyruvic acid enters the mitochondrion. Here it is converted to acetyl coenzyme A. A molecule of carbon dioxide is given off. At the beginning of the KrebsÂ’ Cycle acetyl coenzyme is present. It releases a further two molecules of carbon dioxide gas. Hydrogen atoms released from the KrebsÂ’ Cycle are passed along the hydrogen and electron carrier system. Final products of this system include 3 molecules of ATP. Finally, the hydrogen atoms combine with oxygen to form water, which allows the reactions to continue. Anaerobic respiration of the yeast cells begins to take place in the conical flask when there is no longer any oxygen available.

[IMAGE]Glucose carbon dioxide + ethyl alcohol + less energy

Enzymes have active sites. This is the binding site on the surface of the enzyme molecule for the substrate molecules. An enzymeÂ’s active site has regions that
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