Which is most abundant in chloroplast ?

Options

A. Aldolase
B. RuBP carboxylase
C. Phosphatase
D. Transketolase.

Answer

**Step-by-Step Solution:**

1. **Understanding Chloroplasts**: Chloroplasts are organelles found in plant cells and are essential for the process of photosynthesis, where plants convert light energy into chemical energy.

2. **Photosynthesis Process**: Photosynthesis consists of two main reactions: the light-dependent reactions and the light-independent reactions (also known as the dark reactions). The light reactions capture energy from sunlight, while the dark reactions synthesize glucose.

3. **C3 Cycle**: In the dark reactions, a process known as the C3 cycle occurs. This cycle involves the fixation of carbon dioxide into a 5-carbon sugar called ribulose bisphosphate (RuBP).

4. **Role of Rubisco**: The enzyme ribulose bisphosphate carboxylase/oxygenase (commonly known as Rubisco) plays a crucial role in the C3 cycle. It catalyzes the carboxylation of RuBP, leading to the formation of 3-carbon molecules called phosphoglyceric acid.

5. **Abundance of Rubisco**: Rubisco is not only vital for photosynthesis but is also recognized as the most abundant protein on Earth, particularly in the plant kingdom. This makes it the most abundant protein found in chloroplasts.

6. **Conclusion**: Based on the information provided, the most abundant component in chloroplasts is the enzyme Rubisco.

**Final Answer**: Rubisco (Ribulose bisphosphate carboxylase/oxygenase) is the most abundant protein in chloroplasts.

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