Helps produce energy for eukaryotic cells when oxygen is abundant

Helps produce energy for prokaryotic or eukaryotic cells via anaerobic fermentation

Takes in ammonia, a byproduct of amino acid catabolism, and converts it into harmless urea

Breaks down fatty acids through a cyclical series of steps that produces acetyl-CoA

Contains hydrolytic enzymes to degrade and recycle organic compounds

In eukaryotes, the cleavage of citrate to form acetyl-CoA takes place in the cytosol

Although some citric acid cycle intermediates are precursors to other biosynthetic pathways, no other biosynthetic pathways produce citric acid cycle intermediates

Anaplerotic reactions remove metabolites from the citric acid cycle

All organisms except archaea have a complete citric acid cycle

Enolase

Fumarase

Aconitase

Succinate dehydrogenase

Pyruvate

Citrate

Acetyl-CoA

Glucose

both anabolic and catabolic

anabolic

catabolic

neither anabolic, nor catabolic

linear

. . .

. . .

. . .

. . .

Carbon dioxide

Methane

Nitric oxide

Nitrous oxide

Citrate cis-aconitate isocitrate alpha-ketoglutarate succinyl-CoA succinate fumarate malate oxaloacetate

Citrate cis-aconitate isocitrate alpha-ketoglutarate succinate succinyl-CoA fumarate malate oxaloacetate

Citrate cis-aconitate isocitrate alpha-ketoglutarate succinyl-CoA succinate malate fumarate oxaloacetate

Citrate cis-aconitate isocitrate succinyl-CoA alpha-ketoglutarate succinate fumarate malate oxaloacetate