How much assimilatory power is produced per molecule of oxygen produced in light reaction ?

Options

A. `2ATP + 1NADPH_(2)`
B. `2ATP +2NADPH_(2)`
C. `1ATP +1NADPH_(2)`
D. `1ATP + 2NADPH_(2)`

Answer

To determine how much assimilatory power is produced per molecule of oxygen during the light reaction of photosynthesis, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Light Reaction**: The light reaction of photosynthesis occurs in the thylakoid membranes of chloroplasts and involves the absorption of light energy. This energy is used to split water molecules (photolysis), producing oxygen, protons, and electrons.

2. **Photolysis of Water**: During photolysis, one molecule of water (H₂O) is split to produce one molecule of oxygen (O₂), along with electrons and protons. The overall reaction can be summarized as:
\[ 2H₂O \rightarrow 4H^+ + 4e^- + O₂ \]
This means that for every 2 molecules of water, 1 molecule of oxygen is produced.

3. **Production of ATP and NADPH**: In the light reaction, the electrons produced from the photolysis of water are transferred through a series of proteins (electron transport chain) associated with Photosystem II (P680) and Photosystem I (P700). This process results in the formation of:
- 2 molecules of ATP
- 2 molecules of NADPH

4. **Assimilatory Power Calculation**: The assimilatory power refers to the energy stored in the form of ATP and NADPH, which can be used in the dark reactions (Calvin cycle) for the synthesis of glucose. Since 1 molecule of oxygen is produced from the splitting of 2 molecules of water, we can see how much assimilatory power is generated per molecule of oxygen:
- For 2 molecules of water (producing 1 O₂), we obtain 2 ATP and 2 NADPH.

5. **Final Calculation**: Therefore, for each molecule of oxygen produced, the total assimilatory power (in terms of ATP and NADPH) is:
- 2 ATP + 2 NADPH

### Conclusion:
Thus, the assimilatory power produced per molecule of oxygen is 2 ATP and 2 NADPH.