Question

Find out the correct combinations concerning components of photosynthetic electron transport, location in relation to thylakoid and action.
I. OEC - Iumen side - water reduction.
II. Plastocyanin - lumen side - electron transfer from cyt f to PSI.
III. Ferrodoxin - stroma side - reduction of $NA{D}^{+}$ to $NADH$.
IV. Cytochrome complex - integral protein - transfer electrons from $PQ{H}_2$ to PC.
Choose the correct answer.

• A. II and IV
• B. I and III
• C. II and III
• D. I and IV.

Answer 1

The correct option is A II and IV

During electron transport chain in Z scheme of noncyclic photophosphorylation, electron carriers in series are as :-

• Activation of chlorophyll results in excitaion of electron which then helps in splitting of water.
  
• Photolysis of water, results in generation of oxygen and protons which later used for generation of ATP and electron which enters in PS II.
  
• In PS II, electrons first accepted by plastoquinone (PQ) and form PQH2, this PQH2 transfer electrons to cytochrome b and become PQ then to cytochrome f. These cytochrome complex are integral proteins present on thylakoid membrane.
  
• From cytochrome f to last acceptor of PS II i.e., plastocyanin present on lumen side of thylakoid.
• From plastocyanin, electrons flow reaches to PSI, electrons then captured by Fe-S protein, from Fe-S protein to ferredoxin present on lumen side for generation of NADH.

Thus option II and IV are correct.