Energy Transfer In And Between Organisms: - Glycolysis

- 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 

1. Glycolysis 
2. Link reaction 
3. Kreb cycle 
4. 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