when o2 is added to an anaerobic suspension of cells consuming glucose at a very high rate, the rate of glucose consumption declines greatly and the accumulation of lactate ceases. this is called the pasteur effect, which occurs in most cells that are capable of both anaerobic and aerobic glucose catabolism. a) why does the accumulation of lactate cease after o2 is added? b) why does the presence of o2 decrease the rate of glucose consumption?