Energy Transfer:

Cellular Respiration

G.BurgessUpdated 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 CO2

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 + CO2 + H2O

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

http://library.thinkquest.org/27819/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 CO2. **Each time CO2 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.