In the absence of oxygen cells consume glucose at a high ste

In the absence of oxygen, cells consume glucose at a high, steady rate. When oxygen is added, glucose consumption drops dramatically and then maintained at a lower rate. Why is glucose consumed at a high rate in the absence of oxygen and a low rate in its presence?

Solution

Answer:

In the absence of oxygen, cells consume glucose at a high, steady rate. When oxygen is added, glucose consumption drops due to Pasteur effect.

Anaerobic conditions produce small amount of ATP, but consumption of glucose is faster. When oxygen is added, glucose consumption drops dramatically as the ATP and Citrate production increases and the rate of glycolysis slows, since the ATP and citrate produced act as allosteric inhibitors for phosphofructokinase 1, an enzyme in the glycolysis pathway.