Electron carriers are compounds acting as relays in cell that transfer electrons from initial electron donor to final electron acceptor. They themselves are oxidized and reduced. For sugars, aerobic and fermentative reactions diverge at pyruvate. Not all reactions use Embden Meyerhof pathway. Aerobic respiration requires molecular oxygen 2.
Anaerobic respiration can use nitrate, sulfate, etc. as electron acceptor.
Example of aerobic respiration, with glucose as energy source. Unlike in fermentation, glucose can be completely oxidized. Some substrate-level phosphorylation. But also oxidative phosphorylation. Each carrier has a different redox potential and electrons are passed from carriers with more negative redox potentials to those having more positive redox potentials.