Transfer of Energy from Light Reaction to Dark Reaction:

The Light Reaction and Dark Reaction are two phases of photosynthesis. The light reaction takes place in the presence of light and produces ATP and NADPH as energy carriers. In the dark reaction, the energy from ATP and NADPH is used to fix carbon dioxide into glucose. The transfer of energy from the light reaction to the dark reaction is essential for the process of photosynthesis to occur.

The energy is transferred in the form of ATP (Adenosine Triphosphate). ATP is a high-energy molecule that is produced during the light reaction. It is the primary energy carrier in living organisms. ATP is synthesized during the light reaction by the process of photophosphorylation.

Photophosphorylation:

Photophosphorylation is the process by which ATP is synthesized during the light reaction. It occurs in two ways:

1. Non-cyclic photophosphorylation: In this process, the energy from light is absorbed by the chlorophyll molecules in the thylakoid membrane. This energy is used to transfer electrons from water to NADP+ through a series of electron carriers. This generates a proton gradient that is used to produce ATP through ATP synthase.

2. Cyclic photophosphorylation: In this process, the electrons released during the electron transport chain are cycled back to the photosystem I. This generates a proton gradient that is used to produce ATP.

Transfer of ATP to Dark Reaction:

Once ATP is synthesized during the light reaction, it is transferred to the stroma of the chloroplast where the dark reaction occurs. The ATP is used to power the Calvin cycle, which is the series of reactions that converts carbon dioxide into glucose.

The ATP provides the energy required for the conversion of ribulose bisphosphate (RuBP) into 3-phosphoglycerate (3-PGA) by the enzyme Rubisco. This is the first step in the Calvin cycle. The energy from ATP is also used to convert glyceraldehyde-3-phosphate (G3P) into glucose.

Conclusion:

In conclusion, the energy obtained from the light reaction is transferred to the dark reaction in the form of ATP. ATP is synthesized during the light reaction by the process of photophosphorylation. The ATP is used to power the Calvin cycle in the dark reaction, which is the process by which carbon dioxide is converted into glucose.

Energy currency will be ATP in any case.