When O2 is added to an anaerobic suspension of cells consuming glucose at a high rate, the rate of glucose consumption declines greatly as the O2 is used up, and accumulation of lactate ceases. This effect, first observed by Louis Pasteur in the 1860s, is characteristic of most cells capable of both aerobic and anaerobic glucose catabolism, like muscle cells in our body.
A) Why does the accumulation of lactate cease after O2 is added? Outline briefly the metabolic pathways involved in glucose breakdown in both conditions.
B) Explain why does the presence of O2 decrease the rate of glucose concumption?