Energy Transfer: Cellular Respiration G.Burgess Updated 2010.

Release of stored energy  Two forms: Anaerobic: releases energy when oxygen is not present = fermentation Aerobic: releases energy using oxygen

Anaerobic Respiration  Fermentation: performed by yeast: converts glucose to carbon dioxide and ethanol when releasing energy. 2ATP + Glucose  2 pyruvic acid molecules (3C molecules) + 4ATP The pyruvic acid is then converted to ethanol and CO 2  This conversion releases H + to NAD + molecules Bacteria also perform anaerobic respiration  Convert pyruvic acid to lactic acid.  This is a similar reaction that occurs in over stressed muscle cell.

Aerobic Respiration  Most efficient for ATP production  Three main processes; Glycolysis: cytoplasm Krebs Cycle: outer membrane of mitochondria Electron Transport Chain: inner membrane of mitochondria  Reactants: Glucose and oxygen  Products: ATP + CO 2 + H 2 O

Glycolysis  Anaerobic phase  requires 2 ATP  Glucose is converted to pyruvic acid releasing H + and 4 ATP  H + is picked up by NAD + (nicotinamide adenine dinucleotide) and transported to the electron transport chain

y.thinkque st.org/278 19/media/ glycolysis. gifhttp://librar y.thinkque st.org/278 19/media/ glycolysis. gif, accessed Oct.14, 2007

Krebs Cycle  AKA: Citric Acid Cycle  Changes pyruvic acid to different carbon molecular forms.  The changing of the molecule releases H + ’s, GTP and CO 2.  **Each time CO 2 is released, oxygen was used.  NAD and FAD are ion acceptor molecules in this stage  NAD and FAD transport H + ’s to the electron transport chain.  GTP is converted to ATP for useable molecular energy.  2 ATP are formed

Electron Transport Chain  AKA: oxidative phosphorylation  Electron acceptor molecules transport electrons (H ions) to the inner membrane of the mitochondria  The electrons are passed from one electron acceptor to another stronger one.  Each time the electron is passed energy is given off  Energy is collected as ADP joins P to form ATP.  Approx. 32 ATP are formed

Net Energy  **Not all the energy formed is converted to ATP Energy not collected by ATP is released as heat energy. This is partly the reason why we are warm blooded organisms.