1. RESPIRATION

2. Energy in food Carbohydrates (17 kJ g -1 ) Proteins (17 kJ g -1 ) Lipids (34 kJ g -1 ) These are sources of reduced carbon This can supply hydrogen atoms  protons (H + ) + electrons (e - ) © 2010 Paul Billiet ODWSODWS

3. Energy transformations Light  Chemical (mostly in chemical bonds) Chemical  Heat Chemical  Kinetic (movement) Chemical  Chemical COUPLED REACTIONS e.g. Food  ATP © 2010 Paul Billiet ODWSODWS

4. The energy in Adenosine Triphosphate (ATP) ADP + Pi  ATP + H 2 O  E = + 30.5 kJ mol -1 Inorganic phosphate High energy bond ADENOSINE  P  P  P © 2010 Paul Billiet ODWSODWS

5. A stepwise energy release is needed Complete oxidation of glucose C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O  E = 2880 kJ mol -1 Complete oxidation of a fat (lipid) C 18 H 34 O 2 + 25.5O 2  18CO 2 + 17H 2 O  E = 9800 kJ mol -1 © 2010 Paul Billiet ODWSODWS

6. Respiration is efficient This is too much to handle all at once Energy is released step by step Coupled to ATP synthesis The energy in 1 molecule of glucose is used to synthesise 36 molecules of ATP 37.5 % efficient This is a very efficient energy conversion Because the release of the energy from the food molecules is done stepwise © 2010 Paul Billiet ODWSODWS

7. Coupling the energy released from glucose to ATP Two reaction pathways GLYCOLYSIS in the cytoplasm KREB'S CYCLE in mitochondria of eukaryotes (in the cytoplasm of prokaryotes) © 2010 Paul Billiet ODWSODWS