Oxygen gas released during photosynthesis is formed during

Options

A. oxidative phosphorylation
B. cyclic phosphorylation
C. non-cyclic photophosphorylation
D. substrate level phosphorylation

Answer

**Step-by-Step Solution:**

1. **Understanding Photosynthesis:** Photosynthesis is the process by which green plants, algae, and some bacteria convert light energy into chemical energy, primarily in the form of glucose. During this process, oxygen is released as a byproduct.

2. **Identifying the Stages of Photosynthesis:** Photosynthesis consists of two main stages: light reactions and dark reactions (Calvin cycle). The light reactions occur in the thylakoid membranes of chloroplasts and are responsible for capturing light energy.

3. **Types of Photophosphorylation:** There are two types of photophosphorylation that occur during the light reactions:
- **Cyclic Photophosphorylation:** Involves only Photosystem I and does not produce oxygen.
- **Non-Cyclic Photophosphorylation:** Involves both Photosystem I and Photosystem II and is responsible for the production of oxygen.

4. **Role of Water Splitting:** In non-cyclic photophosphorylation, water (H₂O) is split into oxygen (O₂), protons (H⁺), and electrons (e⁻). This process is known as photolysis of water and occurs at Photosystem II.

5. **Oxygen Production:** The oxygen gas released during photosynthesis comes specifically from the splitting of water molecules. This process occurs in non-cyclic photophosphorylation, where both Photosystem I and II are involved.

6. **Conclusion:** Therefore, the correct answer to the question is that the oxygen gas released during photosynthesis is formed during **non-cyclic photophosphorylation**.

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