Question

Bacterial photosynthesis involves

• A. Both PS-I and PS-II
• B. PS-II only
  
• C. PS-I only
• D. None of the above

Answer 1

Answer: (C)

PS-I only

Bacterial photosynthesis is based on cyclic photophosphorylation mechanism and only PS-I is involved in it. Photosynthesis first evolved as an anoxygenic process in bacteria that were similar to the current green sulphur bacteria, where the transmission of an electron from the photosystem is accompanied by the extraction of a proton from hydrogen sulphide (H₂S), producing sulphur as a by-product. The advent of oxygenic photosynthesis provided an organism not only with ATP, but also with a stable energy source in the form of organic compounds that can be stored for later use.The transition from anoxygenic to oxygenic photosynthesis involved an extension of the existing system, whereby new reactions were added on to existing ones. This was achieved through a remarkable increase in protein complexity with the development of a second photosystem, photosystem II (PSII).

So, the correct answer is option C.