Question

All of these are associated with Photosystem II except

• A. Electron transport chain
• B. A reaction center
• C. ATP
• D. NADPH
• E. Water

Answer 1

Answer: (A)

Electron transport chain

Photosystem II or PS II is a photosynthetic pigment system along with some electron carriers that is located in the appressed part of grana thylakoids. The PS II contains chlorophyll-b and some forms of chlorophyll-a.

*PS II picks up electron released during photolysis of water and the electron is extruded as the light energy is absorbed by PS II.

*PS II is composed of following pigment molecules:

Chl-a : one molecule- reaction centre

Chl-a 670: 200 molecules- Antenna chlorophyll

Chl-b: upto 200 molecules- Accessory pigments

Carotenoids: up to 50 molecules- Accessory pigments

*PS II takes part in non cyclic photophosphorylation which results in the formation of ATP and NADPH.

Hence options 'A reaction centre, ATP, NADPH and Water' are associated with Photosystem II.

Electron Transport Chain or ETC is present in the inner mitochondrial which contains various enzymes and co-enzymes and act as hydrogen and electron carriers. Hence ETC is not associated with Photosystem II.

So, the correct answer is 'Electron transport chain'.