Oxygen. This process is also known as Anaerobic respiration
2 ATP molecules are used, therefore 4 produced.
In the absence of oxygen, yeast and bacteria carry out fermentation in which they partially break down glucose to produce energy. This process yields 2 ATP molecules along with byproducts such as ethanol or lactic acid.
34 ATP molecules are produced by the end of the electron transport chain.
The net gain of ATP molecules at the end of glycolysis is 2 ATP molecules. While 2 ATP molecules are consumed in the initial steps, a total of 4 ATP molecules are produced, resulting in a net gain of 2 ATP molecules.
The glycolysis process produces a net of 2 ATP molecules, while the Krebs cycle produces 2 ATP molecules directly. So, combining these, a total of 4 ATP molecules are produced from one molecule of glucose.
2 ATP molecules
Two, net.
2 ATP are produced in anaerobic respiration(fermentation)
Nadh and ATP
Glycolysis produces a net of 2 ATP molecules per glucose molecule.
2
2