Which of the following is not true of an anticodon ?

Answer

To determine which statement about an anticodon is not true, let's analyze each option step by step.

### Step-by-Step Solution:

1. **Understanding Anticodon**: An anticodon is a sequence of three nucleotides found on tRNA (transfer RNA) that is complementary to a codon on mRNA (messenger RNA). Its primary role is to ensure that the correct amino acid is added during protein synthesis.

2. **Evaluating the Options**:
- **Option 1**: "It is the basic unit of the genetic code."
- This statement is **not true**. The basic unit of the genetic code is the **gene**, not the anticodon. Genes are segments of DNA that code for proteins.

- **Option 2**: "It is present on tRNA molecule."
- This statement is **true**. The anticodon is indeed found on one end of the tRNA molecule, allowing it to pair with the corresponding codon on the mRNA during translation.

- **Option 3**: "It may pair with more than one codon especially if it has the base inosine in its first position."
- This statement is **true**. Inosine can pair with multiple bases, allowing for flexibility in codon-anticodon pairing, which is important for the translation process.

3. **Conclusion**: Based on the analysis, the statement that is not true about an anticodon is: **"It is the basic unit of the genetic code."**

### Final Answer:
The statement that is not true of an anticodon is: **"It is the basic unit of the genetic code."**

---