The biosynthesis of chlorophylls and heme begins with the synthesis of δ‐aminolevulinic acid (ALA) from glutamic acid. 

Two molecules of ALA react to yield porphobilinogen (PBG). 

Four molecules of PBG form the ring structure of protoporphyrin IX, the common branch point for the synthesis of heme and chlorophyll. 

To make chlorophyll, a magnesium chelatase inserts Mg into the protoporphyrin IX ring

TLS Online TPP Program

#Id: 9575

#Unit 11. Evolution and Behavior

TLS Online TPP Program

#Id: 9576

#Unit 11. Evolution and Behavior

Pre Cambrian- Earliest eukaryotes and multicellular eukaryotes. Oxygen levels increase

TLS Online TPP Program

#Id: 9577

#Unit 11. Evolution and Behavior

Cambrian - Most marine invertebrates. Ozone layer forms

TLS Online TPP Program

#Id: 9578

#Unit 11. Evolution and Behavior

Ordovician - Primitive plants and fungi colonize land, first jawless vertebrates,  Mass extinction at end of period

TLS Online TPP Program

#Id: 9579

#Unit 11. Evolution and Behavior

Silurian - Origin of jawed fishes and arthropods, Invasion of land by primitive land plants

TLS Online TPP Program

#Id: 9580

#Unit 11. Evolution and Behavior

Devonian - First amphibian and first seed plant appear, and insects Mass extinction late in period