Aerobic Respiration needs oxygen for the complete breakdown of glucose into carbon dioxide and water. Energy is released in the form of ATP and heat.
Thereare three enzyme-controlled chemical pathways in Aerobic Respiration
Glycolysis
Krebs cycle
Electron transfer chain
Stages in Aerobic Respiration
A) Glycolysis
B) Krebs Cycle
Glycolysis
It is the first chemical pathway that occurs in cellular respiration. It takes place in the cytoplasm of the cell.
Each glucose molecule is broken down into two pyruvate molecules and 2 ATP molecules.
Glucose → 2 Pyruvate + 2 ATP
The Krebs Cycle (Citric Acid)
It is the second chemical pathway of aerobic respiration, and it occurs in the matrix of the mitochondria.
Pyruvate (in the form of acetyl CoA) is fed into a complex biochemical cycle, resulting in extensive rearrangement of the molecules. CO2 and H atoms are produced.
Pyruvate → CO2 + H atoms
CO2 is a waste product and diffuses out of the mitochondria and cell. H atoms are transferred by a carrier molecule (NAD) to the third chemical pathway.
The Electron Transfer Chain
It is the final chemical pathway of aerobic respiration. It occurs in the cristae of the mitochondria.
H atoms are ionised(they lose an electron) and the electrons are passed along a series of protein complexes attached to the cristae.
As the electrons are ‘bounced’ along the electron transfer chain, their energy is used to form ATP from ADP.
The Electron Transfer Chain
At the end of the electron transfer chain, the electrons are returned to the H ions, which become atoms again and combine with O2 to form H2O.
This produces the most ATP. One molecule of glucose that undergoes cellular respiration gives 36 molecules of ATP.
Therefore, 38 molecules of ATP are produced throughout the whole process.
