There are three main stages in the cellular respiration
1.Glycolysis
Glucose is turned into two molecules of pyruvate. This process takes place inside the cytoplasm and does not require O2
2.Kreb's cycle(TCA cycle)
This proces takes place in the mitochondrial matrix.Electrons are incorporated in the molecules that will be used in the next step.
3.Electron transport chain
This process takes place in the mitochondrial membrane. Energy from the electrons resulted in the krebs cycle is used to pump protons in the inter membranous space to form an electro chemical gradient. This will lead to the oxydative phosphorilation(ATP synthesis)