Best defined function of manganese in green plants is

Best defined function of manganese in green plants is
  1. photolysis of water
  2. Calvin cycle
  3. nitrogen fixation
  4. water absorption

Solution

Photolysis of water requires light energy, an Oxygen Evolving Complex (OEC) and electron carrier 1/2. OEC complex was formerly called Z-enzyme. It has four Mn ions. Light energy brings about changes in $\mathrm{Mn}\left(\mathrm{Mn}^{+2}, \mathrm{Mn}^{3+}, \mathrm{Mn}^{+4}\right)$ which helps in removing electrons from $\mathrm{OH}^{-}$component of water forming oxygen. Liberation of oxygen also requires $\mathrm{Cl}^{-}$and $\mathrm{Ca}^{+2}$.

Asked in: NEET 2012 (Screening)

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