In the absence of oxygen, fermentation allows...

Question

1. some ATP energy to still be made
2. all options are correct
3. cytochrome oxidase to be oxidized
4. an electrochemical gradient to be maintained for chemiosmosis
5. FADH2 to be oxidized so that glycolysis can continue

Answer 1

The answer to this questions is option 1.

Fermentation is the process by which NADH is oxidized back to NAD+ to be regenerated so that glycolysis can continue (making option 5 incorrect). This occurs in the absence of oxygen and therefore the steps of oxidative phosphorylation (which includes the oxidation of cytochrome c and the establishment of an electrochemical gradient) which rely on oxygen cannot occur. Therefore option 3 and 4 are incorrect.

Fermentation allows glycolysis to continue and the 2 net ATP that it generates from each mole of glucose to be utilized by the cell. While this is far less than the 32+ ATP that is generated by complete oxidative phosphorylation, some energy is still generated, allowing the cell to continue its vital functions.

I hope this explanation helps! If you are still looking for help with this topic or any other biology topics like it, please feel free to reach out to start a lesson!

Best of luck,

Brandon