Protein present in cartilage & bone :-

Options

A. Chondrin & ossein respectively
B. Chondrotin sulphate
C. Cartilagein
D. None

Answer

### Step-by-Step Solution:

1. **Identify the Tissues**: The question asks about proteins present in cartilage and bone. We need to focus on these two types of connective tissues.

2. **Understand Bone Composition**: Bones are metabolically active tissues made up of various cells. The key cells involved are:
- **Osteoblasts**: These are responsible for the formation and mineralization of bone.
- **Osteocytes**: These are mature bone cells that maintain bone tissue.
- **Osteoclasts**: These cells are involved in the reabsorption of bone tissue.

3. **Understand Cartilage Composition**: Cartilage is made up of specialized cells known as:
- **Chondrocytes**: These cells produce a large amount of the extracellular matrix, which includes collagen and other proteins.

4. **Identify Key Proteins**:
- In **cartilage**, the main protein present is **chondrin**. This protein is crucial for the structure and function of cartilage.
- In **bone**, the primary protein is **osteocalcin** (often referred to as "ursine" in some contexts), which is involved in bone mineralization and metabolism.

5. **Conclusion**: The proteins present in cartilage and bone are:
- **Cartilage**: Chondrin
- **Bone**: Osteocalcin (or "ursine")

### Final Answer:
The protein present in cartilage is **chondrin**, and the protein present in bone is **osteocalcin (ursine)**.

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