Question

Differentiate between Oxygenic and Anoxygenic photosynthesis?

Answer 1

Photosynthesis is an anabolic process in which the green plants synthesize the food in the presence of sunlight. The sunlight captured by light absorbing pigments such as chlorophyll. Photosynthesis is a vital process for the photoautotrophs.

Complete answer:
Bacterial photosynthesis involves two types of photosynthesis which are oxygenic and Anoxygenic photosynthesis. Photosynthetic bacteria contain light absorbing pigments and reaction centres which convert sunlight into chemical energy.

Oxygenic photosynthesis	Anoxygenic photosynthesis
This type of photosynthesis involves oxygen release. Photolysis of water occurs in this process which results in release of oxygen as a by-product.	This type of photosynthesis does not involve release of oxygen.
Water is used as a source of reducing agent in the green plants and cyanobacteria.	Anoxygenic photosynthesis occurs in purple, green sulfur, filamentous Anoxygenic photoautotrophs and phototrophic heliobacteria.
Oxygenic photosynthesis occurs in various types of bacteria and in green plants.	Anoxygenic photosynthesis uses ${H_2}S$ and thiosulfate as a reducing agent because they are incapable of using water as a reducing agent.
Oxygenic photosynthetic bacteria are unicellular or multicellular. These bacteria perform photosynthesis in a similar manner to plants.	It uses photosystem 1 to generate ATP.
They contain light harvesting pigments such as phycobilins and phycoerythrin which absorbs carbon dioxide and releases oxygen.	It uses bacteriochlorophyll instead of chlorophyll.
This process involves two photosystems to generate ATP. Photosystem 1 and photosystem 2.	Carbohydrates synthesized in this process which results in the release of oxygen and removal of carbon dioxide from atmosphere
Cyanobacteria are blue-green in colour and mostly found in water but can survive on lands and rocks.

Note: Photosynthetic bacteria used as bio-fertilizers. They are used in the treatment of polluted water because they utilize toxic substances such as ${H_2}S$ and thiosulphate. Photosynthetic bacteria also contain Carotenoids, bacteriorhodopsin as light harvesting pigments.