Assertion :-Sickle-cell anaemia is caused by the substitution of glutamic acid by valine at the sixth position of the beta globin chain of the hemoglobin moecule.
Reason :- It is due to the single base substitution at the sixth codon of the beta globin gene from GUG to GAG.

Options

A. If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion.
B. If both Assertion & Reason are trur but Reason is not a correct explanation of the Assertion.
C. If Assertion is True but the Reason is Flase.
D. If both Assertion & Reason are false.

Answer

**Step-by-Step Solution:**

1. **Understanding the Assertion:**
- The assertion states that sickle-cell anemia is caused by the substitution of glutamic acid by valine at the sixth position of the beta globin chain of hemoglobin.
- This is true because sickle-cell anemia is indeed caused by this specific substitution, which affects the structure and function of hemoglobin.

2. **Understanding the Reason:**
- The reason provided states that this substitution is due to a single base substitution at the sixth codon of the beta globin gene from GUG to GAG.
- This statement is incorrect. The correct substitution is from GAG (which codes for glutamic acid) to GUG (which codes for valine).

3. **Identifying the Nature of the Disorder:**
- Sickle-cell anemia is classified as an autosomal recessive disorder, meaning that two copies of the mutated gene (one from each parent) are necessary for the individual to express the disease.

4. **Conclusion:**
- Since the assertion is true and the reason is false, we conclude that the correct answer is that the assertion is true, but the reason is false.

**Final Answer:**
- Assertion is true, and Reason is false.

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