Which amino acid is substituted in sickle cell anamia ?

Options

A. Gutamic acid by valine in `alpha`-chain
B. Glutamic acid by valine in `beta`-chain
C. Valine by glutamic acid in `beta`-chain
D. Valine by glutamic acid in `alpha`-chain

Answer

**Step-by-Step Solution:**

1. **Understanding Sickle Cell Anemia**: Sickle cell anemia is an inherited disorder that affects the red blood cells. In this condition, the red blood cells become misshapen (sickle-shaped) and are less effective at carrying oxygen throughout the body.

2. **Identifying the Genetic Basis**: The disorder is caused by a mutation in the gene that codes for the beta chain of hemoglobin, which is the protein in red blood cells responsible for oxygen transport.

3. **Locating the Mutation**: The specific mutation occurs at the 6th codon of the gene coding for the beta chain of hemoglobin. This codon is responsible for coding a specific amino acid in the hemoglobin protein.

4. **Identifying the Amino Acids Involved**: In normal hemoglobin, the 6th amino acid is glutamic acid. In individuals with sickle cell anemia, this glutamic acid is substituted with valine due to the mutation.

5. **Conclusion**: Therefore, the amino acid that is substituted in sickle cell anemia is glutamic acid, which is replaced by valine.

**Final Answer**: The amino acid that is substituted in sickle cell anemia is glutamic acid, which is replaced by valine.

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