In his studies of alcoholic fermentation by yeast, louis pasteur noted that the sudden addition of oxygen (o2) to the previously anaerobic culture of fermentation grape juice resulted in a dramatic decrease in the rate of glucose consumption. this "pasteur effect" can be counteracted by the addition of 2,4-dinitrophenol (dnp), an uncoupler of oxidative phosphorylation. (6 marks) (a) why would the yeast cells consume less glucose in the presence of oxygen? (b) why would dnp counteract or prevent the pasteur effect?

A. 38 mol of ATP is yielded during aerobic oxidation of glucose while only 2 ATP is yielded during anaerobic oxidation of glucose. This will cause the yeast cell to need 19 times more glucose anaerobically and to need less glucose aerobically.

(b) DNP is going to block the major step in aerobic ATP production causing the yeast cells to use about the same amount of glucose as anaerobic cells when compared to yeast cells without DNP present

from my research i have to the conclusion that decomposers, such as fungi, bacteria and invertebrates, play a critical role in nutrient cycling and without them the earth's ecosystem may not support life as we know it. elements such as carbon, nitrogen and phosphorus exist in limited amounts on earth, although huge amounts of carbon are being released into the atmosphere from underground sources now by humans. it is still extremely important that other nutrients be retained by the process of re-use. decomposers are organisms that are able to chemically break down dead material and make these elements available for use by other organisms. without this breakdown of dead material, dead bodies would pile up. so decomposers also play a role in clean up also. without them, life might not continue as we know it and dead material would overwhelm the earth.