Question

Choose the odd one for fermentation?
1. It occurs in prokaryotes and unicellular
eukaryotes only
2. It occurs in absence of oxygen
3. Net gain of only two molecules of ATP from
each molecule of glucose
4. There is no any net gain of NADH + H+

Answer 1

• During the absence of oxygen, in anaerobic respiration, the by-products are carbon dioxide and ethyl alcohol. So, the odd one out is 'Starch'.

Answer 2

There is no any net gain  of $NADH^{+}$ $H^{+}$

Fermentation:

• It is a metabolic process.
• In which organisms convert sugar to alcohol or an acid.
• It releases energy.

It takes place anaerobically. The initial step in fermentation is the same as it is in cellular respiration:  

• The creation of pyruvic acid by glycolysis.
• It produces net 2 ATP molecules.  
• Pyruvate is then converted to lactic acid, ethanol, or other compounds in the next phase.
• NAD+ is generated here, and it is re-used in the glycolysis process.