Question

In photosynthetic electron transport systems, Mn ions are associated with_______.
A. \[C{F_0}\]– \[C{F_1}\] complex
B. \[Cyt{b_6}\]– \[Cytf\] complex
C. Oxygen evolving complex
D. plastoquinone

Answer 1

Hint: Photosynthetic electron transport system is the process of light induced electron transport which is used for generation of chemical energy. This is the series of electrons that transfers the electron donor to the electron acceptors. Here, it can be found based on this equation and then analyzed.

Complete answer:
 In photosynthetic electron transport systems, the major role is given through the process of photosynthesis. It means that the ultimate source of all our food and most of the organisms use solar energy to synthesize the biomass and fuels.
Here, we are going to see the complexes which are involved in this system. They are as follows:

PLASTOQUINONE:
It is an isoprenoid quinone molecule which is involved in the electron transport chain.
The role plays here, more specifically in light reactions of photosynthesis, is that mobile electron carrier through the membrane of the thylakoid.
The most common form of plastoquinone is a \[2\], \[3\]-dimethyl- \[1\], \[4\]-benzoquinone molecule with a side chain of nine isoprenyl units.

OXYGEN EVOLVING COMPLEX:
It is also known as a water-splitting complex.
Manganese ions are associated here.
It is a water oxidizing enzyme which is involved in the photo oxidation of water.
This occurs during the light reactions of photosynthesis.

CF0-CF1 COMPLEX:
This is a complex between chloroplast-coupling factor and subunits III of the membrane spanning portion of the chloroplast \[ATP\]synthase.
This complex is done with the photosynthetic electron transport system.

Hence, the correct answer is option (C).

Additional information: Photosynthetic electron transport system is the first stage of photosynthesis. This produces chemically stored energy and uses solar photons to drive electron transport against thermodynamic gradients. This generates high energy chemicals such as \[ATP\]and reduced \[NADPH\]. Both oxygen evolving phototrophs that include cyanobacteria, algae and plants.

Note: It is believed that PSII contains a Mn protein in it that possibly catalyzes the early stages of oxygen evolution. Four hundred molecules of chlorophyll contains five to eight atoms of manganese and four atoms of manganese are required for oxygen evolution.