# What does the light dependent reaction of photosynthesis produce?

May 28, 2016

#### Explanation:

In the non cyclic photophosphorylation light first hits photosystem II where it excites electrons to a higher energy level. The electrons come from the photolysis of a water molecule producing ${O}_{2}$ and ${H}^{+}$ in the thylakoid space. The electron moves through some proteins in the electron transport chain which move ${H}^{+}$ from the stroma to the thylakoid space making a proton gradient.

The electron then moves to photosystem I where it gets excited to a higher energy level again. Then the electron is moved to $N A D {P}^{+}$ reductase, where $N A D {P}^{+}$ are reduced by the electrons.

The proton gradient created between the stroma and thylakoid space cause the ${H}^{+}$ to flow back into the stroma through proteins in the thylakoid membrane called ATP synthase. The movement of the ${H}^{+}$ powers the ATP synthase causing the phosphorylation of ADP to ATP.

For more information on the process of photosynthesis, I suggest this animation.

Photosynthesis can broadly be classified into two parts. They are Light Reactions and Dark Reactions.

#### Explanation:

End products of the Light reaction are ATP, NADPH and Oxygen.
Oxygen escapes into the atmosphere.
ATP & NADPH which is produced is called Assimilatory Power and this will be used in dark reactions of Photosynthesis.