Purple sulfur bacteria; Green non-sulfur bacteria;
Purple bacteria were thought to have been one of the last bacterial groups to evolve, because bacteriochlorophyll--the bacterial version of the light-capturing molecule--is more complex than the chlorophyll used by green plants.
Green and Purple Sulfur Bacteria - Biotech Articles
Microbiological research has demonstrated that there are currently five known branches of microorganisms that are capable of undertaking chlorophyll based photosynthesis. These five branches are purple bacteria (i.e. Rhodobacter ), green sulfur bacteria (i.e. Chlorobium ), green gliding bacteria (i.e. Chloroflexus ), the Gram positive organism Heliobacteria, and the oxygen evolving cyanobacteria (i.e. Synechococcus ). Cyanobacteria are the only known bacterial group that are capable of evolving oxygen as a byproduct of photosynthesis. Phylogenetic analyses indicate that cyanobacteria are closely related to plant and algal chloroplasts which is the organelle that houses the photosystem in eukaryotic cells.
They use a PSI type reaction center.
The primary pigment involved is bacteriochlorophyll g, which is unique to the group and has a unique absorption spectrum; this gives the heliobacteria their own environmental niche.
Phototrophy takes place at the cell membrane, which does not form folds or compartments as it does in purple bacteria.
Even though heliobacteria are phototrophic, they can grow without light by fermentation of pyruvate.
Plants obtain their own food by using the energy they get from the sun.
The plant captures sunlight with the pigment chlorophyll
Then the sunlight turns into food and sugars.
Extra is called ATP.