Photophosphorylation means synthesis of

Options

A. `ATP` from `ADP`
B. `NADP`
C. `ADP` from `ATP`
D. `PGA`.

Answer

### Step-by-Step Solution:

1. **Understanding Photophosphorylation**: Photophosphorylation is the process by which ATP (adenosine triphosphate) is synthesized from ADP (adenosine diphosphate) using light energy. This process occurs during photosynthesis in plants.

2. **Role of Light Energy**: In photophosphorylation, light energy is captured by chlorophyll and converted into chemical energy. This energy is then used to add a phosphate group to ADP, transforming it into ATP.

3. **Electron Transport Chain**: The process involves the electron transport chain, where electrons are transferred through a series of proteins embedded in the thylakoid membrane of chloroplasts. As electrons move through this chain, energy is released, which is used to pump protons (H⁺ ions) across the membrane, creating a proton gradient.

4. **ATP Synthesis**: The energy stored in this proton gradient is then utilized by ATP synthase, an enzyme that synthesizes ATP from ADP and inorganic phosphate (Pi). This process is known as chemiosmosis.

5. **Types of Photophosphorylation**: There are two types of photophosphorylation: cyclic and non-cyclic. In cyclic photophosphorylation, electrons return to the photosystem, while in non-cyclic photophosphorylation, they are transferred to NADP⁺ to form NADPH.

6. **Conclusion**: Therefore, the correct answer to the question "Photophosphorylation means synthesis of" is ATP from ADP.

### Final Answer:
Photophosphorylation means the synthesis of ATP from ADP.

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