Question

Photosynthetic pigment phycobilin is not associated with

• A. PS- II
• B. Cyanobacteria
• C. PS- I
• D. All of the above

Answer 1

The correct option is C PS- I

Phycobilins are the group of photosynthetic pigments found in red algae and cyanobacteria. They are protein linked pigments hence, are called phycobiliproteins. Like chlorophylls, phycobilins are tetrapyrrole but do not contain magnesium and phytol chain. These are found inside sub-microscopic structures called as phycobilisomes attached to thylakoids. The light energy harvested by these pigments is not directly utilised but is transferred to chlorophyll a in the manner similar to carotenoids. Phycobilisomes are responsible for splitting of water and produce oxygen by passing light energy to photosystem II. While many photosynthetic eubacteria possess photosystem I to oxidize reduced molecules such as $H_{2}S$, only cyanobacteria have photosystem II. The evolution of photosystem II apparently occurred in cyanobacteria.

Thus, the correct answer is option C.