Harvesting energy

Genes and DevelopmentBiology 122

Substrate level phosphorylation

Glycolysis

• The overall energy balance for glycolysis is as follows:

Priming -2 ATP [use to add phosphates]Harvest +4 ATP [get from phosphates] +2 NADH__________________________________Net +2 ATP +2 NADH

Oxidation of pyruvate• Acetyl-CoA has a central role in metabolism

• Not only are sugars broken down to acetyl-CoA, but fats are also broken down to it. In addition, some amino acids in proteins also get broken down into acetyl-CoA

• Acetyl-CoA is also used to make fats and some amino acids

The Citric acid cycle

• Energy summary: The complete oxidation of each acetyl-CoA yields

• one GTP (equivalent to one ATP)• 3 NADHs• one FADH2 • two CO2 molecules are released

ATP synthase tutorial (Marcey site)

ATP synthase animation

Without oxygen

NAD+

O2 NADH

ETC in mitochondria

Acetyl-CoA

Ethanol

NAD+

CO2

NAD+

H2O

Lactate

Pyruvate

AcetaldehydeNADH

NADH

With oxygen

KrebsCycle