Photosynthesis in Microorganisms General, Archaen, Anoxygenic, and Oxygenic

General Photosynthesis

Types of Phototrophs – based on Carbon source for synthesis

Fundamentals of Photsynthetic Activity and Cell Arrangement Highly folded inner membrane Thylakoid, lamelle, tubes, vessicles, chlorosomes, grana Pigments Chlorophyll, bacteriochlorophyll, rhodopsin, carotenoid, phycobillins Light reactions electron transport, proton gradient, ATPase

Fundamentals of Photsynthetic Activity and Cell Arrangement Internal Space Stroma, cytoplasm, carboxysome CO2-Fixation Calvin-Bensen Cycle, Reductive TCA cycle, glyoxylate pathway Dark Reactions

Modes or Styles of Photosynthesis Archaean Unique, simple Anoxygenic Various pigments: purple or green H2S or H2 as electron donor Oxygenic Similar to plants and algae H2O as electron donor

Reducing Power? Cyanobacteria, Algae, Plants Electrons from H2O reduce NADP+ to NADPH NADPH used in reduction of CO2 to Glucose

Reducing Power? Purple and green bacteria Electrons from H2S (or H2) reduce NADP+ to NADPH NADPH used in reduction of CO2 to Glucose

Pigments Small differences in Chemical structure Properties Magnesium Porphoryn Phytol Large differences in light absorbed

Carotenoids Chlorophyll

Archaean Photosynthesis Halophilic Bacteria Salterns, sea-salt farms, Dead Sea, Great Salt Lake

Archaean Photosynthesis Halophilic Bacteria Salterns, sea-salt farms, Dead Sea, Great Salt Lake Bacteriorhodopsin Examples Halobacterium

Anoxygenic Phototsynthesis Ancient form of metabolism – predates oxygenic photosynthesis and aerobic respiration Bacteria Designated by Pigments – Purple or Green Electron Donor – Sulfur or Non-sulfur Cyclic Photophosphorylation

Winogradsky Column

Anoxygenic Photosynthetic Bacteria Group Genera Light Reactions Dark Reactions Comments Purple Non-Sulfur Rhodospirillum Rhodobacter Rhodopseudomonas Bchl a, b Red carotenoids H2, ethanol as e- donors (rare heterotroph) N-fixation in some

Anoxygenic Photosynthetic Bacteria Group Genera Light Reactions Dark Reactions Comments Purple Sulfur Chromatium Thiocapsa Ectothiocapsa Bchl a, b Red carotenoids H2S, S e- donors Internal and External Sulfur Granules

Anoxygenic Photosynthetic Bacteria Group Genera Light Reactions Dark Reactions Comments Green Sulfur Chlorobium Bchl c, d, e Green carotenoids (chlorosome) H2S as e- donor May contain gas vesicles

Anoxygenic Photosynthetic Bacteria Group Genera Light Reactions Dark Reactions Comments Green Non- Sulfur Chloroflexus Bchl c, d, e Green carotenoids (chlorosome) H2 as e- donor (rare heterotroph) filamentous