Photosynthetic oxygen-producing cells differ from non-oxygen producing cells in that the former

Options

A. Produce three ATP whereas the latter produce five
B. Produce no NADPH whereas the latter do
C. Reduce ferredoxin whereas the latter do not
D. Contain and use both photosystems I and II

Answer

**Step-by-Step Solution:**

1. **Understanding Photosynthesis**: Photosynthesis is the process by which plants convert light energy into chemical energy, producing glucose and oxygen as byproducts. It occurs in two main stages: the light-dependent reactions (light reactions) and the light-independent reactions (dark reactions).

2. **Light-Dependent Reactions**: These reactions occur in the thylakoid membranes of chloroplasts and require light. During these reactions, water molecules are split (photolysis), releasing oxygen. This is why they are referred to as oxygenic reactions. The light-dependent reactions also produce ATP and NADPH, which are energy carriers used in the dark reactions.

3. **Dark Reactions**: Also known as the Calvin cycle, these reactions do not require light directly and occur in the stroma of chloroplasts. They utilize ATP and NADPH produced in the light-dependent reactions to convert carbon dioxide into glucose. No oxygen is produced in this stage.

4. **Photosystems**: In the light-dependent reactions, two types of photosystems are involved: Photosystem I (PSI) and Photosystem II (PSII). Both of these systems are essential for the production of ATP and NADPH. Photosystem II is primarily responsible for the photolysis of water and the production of ATP, while Photosystem I contributes to the formation of NADPH.

5. **Comparison of Oxygen-Producing and Non-Oxygen Producing Cells**:
- Oxygen-producing cells (like those in green plants) contain both Photosystem I and Photosystem II, leading to the production of oxygen, ATP, and NADPH.
- Non-oxygen producing cells (like some bacteria) do not have these photosystems and therefore do not produce oxygen or the same energy carriers.

6. **Conclusion**: The key difference is that photosynthetic oxygen-producing cells utilize both Photosystem I and II, leading to the production of oxygen, ATP, and NADPH, while non-oxygen producing cells do not have these systems and do not produce oxygen.

**Final Answer**: Photosynthetic oxygen-producing cells differ from non-oxygen producing cells in that the former contain and use both Photosystem I and II, which are responsible for the production of oxygen, ATP, and NADPH.

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