Definition: Aerobic Cellular respiration is a catabolic process which involves the intracellular oxidation of glucose or organic molecules through a series of enzymatic reaction producing energy in the form of ATP with the release of CO2 and H2O as byproducts. It is the most basic metabolic pathway found in Eukaryotic cells.
- Glucose: Glucose is synthesized by plants (producers) during photosynthesis. It is consumed by animals (consumers) and used in glycolysis.
- Oxygen from atmosphere is used in Electron Transport Chain as terminal e- acceptor forming H2O
Products
- Carbon dioxide CO2 is the byproduct released during Kreb’s cycle
- Water is released during ETC as byproduct
- Energy in the form of ATP is released from Glycolysis, Krebs cycle and ETC.
3 stages of cellular respiration:
1. Glycolysis (Glyco=Glucose; lysis= splitting) is the oxidation of glucose (C 6) to 2 pyruvate (3 C) with the formation of ATP and NADH.
2. Link Reaction: Pyruvate is transported to mitochondrion where it is decarboxylated forming acetyl CoA. CO2 is released. Oxidation of the 2C carbon compound forms acetyl group with the loss of hydrogen atom. NAD+ is reduced to NADH+H+
3.The Krebs cycle, Citric acid cycle or TCA cycle is eight step cyclic reactions in which acetyl CoA is oxidized producing CO2, reduced coenzymes (NADH + H+ and FADH2), and ATP.
ETC is the step-by-step transfer of high energy electrons through a series of electron carriers located in multienzyme complexes, finally reducing molecular O2 to form water with the formation of ATP by chemiosmosis.