In adult human haemoglobin, how many protein hains are present?

Answer

To answer the question regarding the number of protein chains present in adult human hemoglobin, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Hemoglobin Structure**: Hemoglobin is a protein found in red blood cells that is responsible for transporting oxygen. It is composed of two main components: globin (the protein part) and heme (the iron-containing part).

2. **Composition of Hemoglobin**: Adult hemoglobin (HbA) is primarily made up of globin protein, which constitutes about 95% of its structure. The remaining 5% is made up of heme.

3. **Identifying the Protein Chains**: The globin part of hemoglobin consists of four polypeptide chains. Specifically, adult hemoglobin is composed of:
- 2 alpha chains
- 2 beta chains

4. **Counting the Chains**: Since there are 2 alpha chains and 2 beta chains, we can calculate the total number of protein chains:
- Total protein chains = 2 (alpha) + 2 (beta) = 4 chains.

5. **Conclusion**: Therefore, the total number of protein chains present in adult human hemoglobin is **4**.

### Final Answer:
In adult human hemoglobin, there are **4 protein chains** (2 alpha chains and 2 beta chains).

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