Explain: Non-cyclic Photophosphorylation.

(N/A) $1$. Definition: Photophosphorylation is the process of synthesizing $ATP$ from $ADP$ and inorganic phosphate $(Pi)$ in the presence of light.
$2$. Mechanism: In non-cyclic photophosphorylation,the two photosystems,$PS-II$ and $PS-I$,work in a series connected by an electron transport chain.
$3$. Process: Electrons are released from $PS-II$ upon light absorption,pass through an electron transport system,and reach $PS-I$. During this transport,a proton gradient is generated,leading to $ATP$ synthesis.
$4$. Final Step: Electrons from $PS-I$ are finally accepted by $NADP^+$ to form $NADPH + H^+$.
$5$. Significance: This process results in the production of both $ATP$ and $NADPH + H^+$,which are essential for the biosynthetic phase of photosynthesis.