Cellular Respiration Aerobic and Anaerobic Metabolism

Glycolysis takes place in the cytoplasm

Glycolysis Simplified (greatly ) If oxygen is available (aerobic), then pyruvate enters the Krebs cycle If oxygen is not available(anaerobic), then pyruvate undergoes fermentation

Aerobic respiration

Synonymous Terms Krebs cycle Citric acid cycle Tri-carboxylic acid cycle (TCA cycle)

Mitochondrial Structure Krebs cycle The Krebs cycle takes place across inner membrane space (matrix) of the mitochondrion

ElectronTransport

The Role of Oxygen (O 2 ) Oxygen is the terminal (final) electron acceptor ½ O 2 + 2H + + 2e -  H 2 O  Oxygen is needed only in the very LAST step of cellular respiration!

Mitochondrial Structure electron transport Infoldings (cristae) increase the area of membrane surface available for electron transport

Aerobic Respiration C 6 H 12 O 6 + 6O 2 → 6CO 2 + 6H 2 O + 38 ATP  The Krebs cycle and electron transport take place in the mitochondria  The Krebs cycle and electron transport maximize ATP yield  38 ATP vs. 2 ATP for fermentation

Anaerobic Respiration (Alcohol Fermentation) C 6 H 12 O 6 → 2 CH 3 CH 2 OH + 2 CO ATP glucose ethyl alcohol carbon dioxide Alcohol fermentation takes place in yeast and some bacteria, and yields only the 2 ATP produced in glycolysis

Anaerobic Respiration (Lactic Acid Fermentation) C 6 H 12 O 6 → 2 C 3 H 6 O ATP glucose lactic acid Lactic acid fermentation takes place in animal cells and some bacteria and fungi; it yields only the 2 ATP produced in glycolysis.