Tryptophan synthesis, carboxylase activity and little leaf of plants are all associated with

Options

A. Zn
B. B
C. Ca
D. Cu

Answer

To solve the question regarding the association of tryptophan synthesis, carboxylase activity, and little leaf of plants, we will analyze each component step by step.

### Step-by-Step Solution:

1. **Understanding Tryptophan Synthesis**:
- Tryptophan is an essential amino acid in plants, and its synthesis involves the enzyme tryptophan synthase.
- This enzyme catalyzes the final steps of tryptophan formation and is crucial for the production of indole acetic acid, a plant hormone.
- **Hint**: Look for the enzymes involved in tryptophan synthesis and their activators.

2. **Role of Zinc in Tryptophan Synthesis**:
- The enzyme tryptophan synthase requires zinc for its activation.
- Thus, zinc is essential for the synthesis of tryptophan in plants.
- **Hint**: Identify the mineral elements that activate key enzymes in amino acid synthesis.

3. **Understanding Carboxylase Activity**:
- Carboxylase enzymes, such as Rubisco and phosphoenolpyruvate carboxylase (PEP carboxylase), are crucial for carbon fixation in plants.
- These enzymes are involved in different metabolic pathways (C3 and C4 photosynthesis).
- **Hint**: Consider the role of carboxylase enzymes in plant metabolism and their activation.

4. **Role of Zinc in Carboxylase Activity**:
- Similar to tryptophan synthase, carboxylase enzymes also require zinc for their activity.
- Zinc influences the function of these enzymes, making it vital for effective carbon fixation.
- **Hint**: Look for the connection between zinc and enzyme activity in plant metabolism.

5. **Understanding Little Leaf Syndrome**:
- Little leaf syndrome is a condition in plants characterized by small, underdeveloped leaves.
- This condition is often a result of zinc deficiency, which is a crucial trace element for plant health.
- **Hint**: Explore the symptoms of mineral deficiencies in plants and their physiological effects.

6. **Conclusion**:
- All three components—tryptophan synthesis, carboxylase activity, and little leaf syndrome—are interconnected through the essential trace element zinc.
- Zinc is necessary for the activation of specific enzymes involved in amino acid synthesis and carbon fixation, and its deficiency leads to physiological disorders like little leaf syndrome.
- Therefore, the correct answer to the question is **Zinc**.

### Final Answer:
The correct answer is **Zinc**.