What is anaerobic respiration? What happens during anaerobic respiration in yeast?

Anaerobic respiration is a type of respiration that occurs in absence or lack of O2. The end products are mostly lactic acid or alcohol. It involves production of less energy only 2 ATP

C6H12O6 → Lactic acid /alcohol + energy

In anaerobic respiration of yeast, pyruvate is converted to ethanol.
Here, pyruvate is decarboxylated to ethanol.
C6H12O6 ——> 2C2H5OH + 2CO2 + Energy
Glucose --> Ethanol + Carbon dioxide + Energy