Question

The correct sequence of flow of electrons in Z-scheme during photosynthesis is?

• A. $H_{2}O\to PSI\to ETS\to PSII\to NA{D}^{+}$
• B. $PSII\to H_{2}O\to ETS\to PSI\to NA{D}^{+}$
• C. $H_{2}O\to PSII\to ETS\to PSI\to NAD{P}^{+}$
• D. $ETS\to PSII\to PSI\to H_{2}O$

Answer 1

The correct option is C $H_{2}O\to PSII\to ETS\to PSI\to NAD{P}^{+}$

Ans is (C) - H2O+PSII+ETS +PSI+NADP+

Whenever molecules gain or lose electrons energy is involved. The Z-scheme is an energy diagram for electron transfer in the "light reactions" of plant photosynthesis. It applies equally well to photosynthesis by algae and cyanobacteria. The vertical energy scale shows each molecule’s ability to transfer an electron to (i.e., to reduce) the next one from left to right. The ones at the top transfer electrons easily to the ones below them as it is a "downhill" reaction, energy-wise. However, for electron transfer from those at the bottom to those above them it is an "uphill" reaction and requires input of outside energy. The Z scheme shows the pathway of electron transfer from water to NADP+.