The codon of m-RNA which determins aminoacid at the 6th position in polypeptide chain of normal haemoglobin is

Options

A. GAG
B. GUG
C. CAC
D. GTG

Answer

To determine the codon of mRNA that specifies the amino acid at the sixth position in the polypeptide chain of normal hemoglobin, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of Hemoglobin**:
Hemoglobin is a protein made up of polypeptide chains. In humans, it consists of two alpha and two beta chains. The question specifically refers to the beta-globin chain.

2. **Identify the Position in Question**:
We are interested in the sixth position of the beta-globin chain.

3. **Know the Codon for Normal Hemoglobin**:
In normal hemoglobin, the codon at the sixth position of the beta-globin chain is known to be GAG.

4. **Determine the Corresponding Amino Acid**:
The codon GAG codes for the amino acid glutamic acid.

5. **Conclusion**:
Therefore, the codon of mRNA that determines the amino acid at the sixth position in the polypeptide chain of normal hemoglobin is GAG.

### Final Answer:
The codon of m-RNA which determines the amino acid at the sixth position in the polypeptide chain of normal hemoglobin is **GAG**.

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