OCR Central Concepts A2 Revision Respiration Need for energy in living things ATP – universal energy currency and synthesis of ATP Glycolysis and Krebs Electron Transport Chain / oxidative Phosphorylation Anaerobic respiration Respiratory substances and respiratory quotients Spiro meters OCR Central Concepts A2 Revision

Energy and respiration Metabolism Total of all biochemical reactions needed for an organism to stay alive Anabolism + catabolism Energy needed to do work Synthesis Active transport Movement Maintenance of body temperature

Photosynthesis and Respiration Energy transfer processes Photosynthesis 6CO2 + 6H2O in the presence of light energy C6H12O6 + 6O2 Respiration C6H12O6 + 6O2 energy is released  6CO2 + 6H2O Most energy transferred to ATP originally derived from light energy

Energy and Living Organisms Transfer of materials and energy in an ecosystem

Adenosine Triphosphate Small water soluble molecule Phosphorylated nucleotide ATPADP = 30.5KJmol-1 energy ATPase ATPsynthase

Synthesis of ATP ATP is formed during respiration (and in photosynthesis

Synthesis of ATP

Mitochondria

Respiration as a REDOX reaction Reduction involves Removal of oxygen Addition of hydrogen Gain of electrons Uptake of energy Oxidation involves Addition of oxygen Removal of hydrogen Loss of electrons Release of energy

Aerobic Respiration The transfer of chemical potential energy from organic molecules to ATP in living cells. Glycolysis Link reaction Krebs cycle Oxidative phosphorylation

Glucose Glycolysis One molecule of glucose is oxidised to two molecules of pyruvate. Phosphorylation Lysis Oxidation Hexose phosphate Hexose biphosphate 2 X triose phosphate (3C) 2 X pyruvate (3C)

Link Reaction Pyruvate is Decarboxylated Dehydrogenated Combined with coenzyme A (adenine, ribose, pantothenic acid) Pyruvate (3C) + coenzyme A------------------acetyl (2C) coenzyme A Carbon dioxide NAD NADred

Krebs Cycle Each cycle releases 2CO2 1 FADred 3NADred 1 ATP

Electron Transport Chain When reduced FAD is oxidised, only two molecules of ATP are formed

Summary of aerobic respiration * * Oxidative phosphorylation

Anaerobic Respiration The Ethanol Pathway

Anaerobic Respiration Lactate Pathway

The Cori Cycle Rescues lactate and prevents waste of its chemical bond energy Prevents fall in plasma pH

Respiratory Substrates Substrate energy density (KJg-1) Carbohydrate 16 Lipid 39 Protein 17 Bomb calorimeter

Respiratory Quotient RQ = Volume of carbon dioxide given off Volume of oxygen taken in Glucose = 1 Lipids = 0.7 Protein = 0.9

Investigating Respiration Respirometer Effect of temperature on respiration Q10 = rate of reaction at temperature t + 10oC rate of reaction at a temperature t