Why doesn't alcoholic fermentation occur in the presence of oxygen?

Question

I read this somewhere in my textbook which said "little or no ethanol is produced in alcoholic fermentation in the presence of oxygen", and I know that alcoholic fermentation is an anaerobic process, but can somebody tell me why doesn't it occur when oxygen is present? How does it interfere with the process when its not needed?

Thanks!

Answer 1

Because, when oxygen is present, automatically aerobic respiration will take place.

the first step of respiration is glycolysis..that is, glucose is broken down to 2 molecules of pyruvates (don't worry, if you're not 10th grade n above i'll make it simple)

the pyruvates, in the presence of oxygen will enter the mitochondria and further steps of aerobic respiration will take place i.e link reaction, Krebs cycle, oxydative phosphorylation..

OTHERWISE, without oxygen, the pyruvates CANNOT enter the mitochondria and remain in cytoplasm where alcoholic fermentation takes place.

hope that helps.