- Glycolysis - 2 Different forms of cellular respiration = Aerobic respiration = requires O₂ produces CO₂, H₂O, ATP Anaerobic respiration = takes place absence of O₂ produces lactate or ethanol and CO₂ // little ATP. Aerobic respiration summeriesed into 4 stages Glycolysis Link reaction Kreb cycle Oxidative phosphorylation Glycolysis 1. Phosphorylation of glucose to glucose phosphate = glucose is made reactive with the addition of 2 phosphate molecules (phosphorylation) // Phosphate molecules come from hydrolysis of ATP (X2) ⇒ ADP. // Energy provided to activate glucose lowering activation energy for enzyme controlled reactions 2. Phosphorylated glucose is split = Glucose is split into 3-carbon triose phosphate (X2) 3. Triose phosphate is oxidised = H₂ removed from triose phosphate (X2) transformed into hydrogen-carrier molecule NAD to form reduced NAD 4. Production of ATP = enzyme controlled reaction converts triose phosphate into 3-carbon molecule Pyruvate // (X2) molecules of ATP are regenerated from ADP. From ONE molecule of glucose = 2 ATP molecules // was 4 but 2 was used in initial phosphorylation of glucose - net increase of 2 molecules. 2 reduced NAD molecules 2 Pyruvate molecules