Coordination compounds have great importance in biological systems. In this context which of the following statements is incorrect:

Options

A. Carboxypeptidase-A is an ennzyme and contains zinc
B. Haemoglobin is the red pigment of blood annd contains iron
C. Cyanocobalamin is `B^(12)` and contains cobalt
D. Chlorophylls are green pigments in plants and contains calcium

Answer

To determine which statement about coordination compounds in biological systems is incorrect, we will analyze each option provided.

### Step-by-Step Solution:

1. **Evaluate Option 1: Carboxypeptidase A**
- Carboxypeptidase A is an enzyme that contains zinc. It is secreted by the pancreas and plays a role in the hydrolysis of proteins.
- **Conclusion**: This statement is **correct**.

2. **Evaluate Option 2: Hemoglobin**
- Hemoglobin is the red pigment in blood and contains iron as its central metal ion. It is crucial for oxygen transport in the body and has an octahedral structure.
- **Conclusion**: This statement is **correct**.

3. **Evaluate Option 3: Cyanocobalamin (Vitamin B12)**
- Cyanocobalamin, also known as Vitamin B12, contains cobalt in its structure. It is essential for various biological functions, including DNA synthesis.
- **Conclusion**: This statement is **correct**.

4. **Evaluate Option 4: Chlorophyll**
- Chlorophyll is the green pigment found in plants and is essential for photosynthesis. It contains magnesium (Mg²⁺) as its central metal ion, not calcium.
- **Conclusion**: This statement is **incorrect**.

### Final Answer:
The incorrect statement is **Option 4: Chlorophyll is the green pigment in plants and contains calcium**.

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