Sudden addition of oxygen (O2) to a previously anaerobic culture of yeast fermenting grape juice results in a dramatic decrease in the rate of glucose consumption. This is known as “Pasteur effect”. a) Why would the yeast cells consume less glucose in the presence of oxygen? Can you estimate how much less glucose the culture would use? b) Pasteur effect can be counteracted by the addition of 2,4-dinitrophenol (DNP), an uncoupler of oxidative phosphorylation. Why would DNP counteract or prevent the Pasteur effect?