Question

The gain of noncyclic electron transport system during the light reaction of photosynthesis is :-

• A. Glucose
• B. Oxygen
• C. $\text{ATP}$ and ${\text{NADPH}}_2$
• D. Both $\text{(B)}$ and $\text{(C)}$

Answer 1

The correct option is D Both $\text{(B)}$ and $\text{(C)}$

When the two photosystems work in a series, first $\text{PS II}$ and then the $\text{PS I}$, a process called non-cyclic photo-phosphorylation occurs. The two photosystems are connected through an electron transport chain, in the $\text{Z}$ scheme. Both $\text{ATP}$ and ${\text{NADPH+H}}^{+}$ are synthesized by this kind of electron flow. Here, the electrons combine with the protons ${\text{H}}^{+}$ which is produced by splitting up of the water molecule and reduces $\text{NADP}$ to ${\text{NADPH}}_2$. Each turn of non-cyclic $\text{ETS}$ produces $\text{1 ATP}$ and ${\text{2NADPH}}_2$ $(4$ mol. of water is photolysed and $1$ ${\text{O}}_2$ is released$)$

So, the gain of noncyclic electron transport system during the light reaction of photosynthesis is oxygen, $\text{ATP}$ and ${\text{NADPH}}_2$.