Question

Photosynthetic bacteria do not contain

• A. PS - I
• B. PS - II
• C. PS - I or PS - III
• D. Quantasome

Answer 1

Answer: (B)

PS - II

There are only two photosystems PS I and PS II. Photosynthetic bacteria have only PS I and absence of PSII makes them carry out cyclic photophosphorylation wherein $H_{2}S$ serves as an electron donor, rather than water, and there is no release of oxygen. The low light intensity and anaerobic conditions favor cyclic photophosphorylation. The correct answer is B.