tRNA recognises amino acyl RNA synthetase by

Options

A. T `Psi` C loop
B. DHU loop
C. Anticodon
D. AA site

Answer

To solve the question "tRNA recognizes amino acyl RNA synthetase by", we will analyze the options provided and determine the correct answer step by step.

### Step-by-Step Solution:

1. **Understanding tRNA and Aminoacyl-tRNA Synthetase**:
- tRNA (transfer RNA) is responsible for bringing amino acids to the ribosome during protein synthesis.
- Aminoacyl-tRNA synthetases are enzymes that attach the correct amino acid to its corresponding tRNA, forming an aminoacyl-tRNA complex.

2. **Identifying Recognition Mechanism**:
- The recognition between tRNA and aminoacyl-tRNA synthetase is crucial for ensuring that the correct amino acid is added to the growing polypeptide chain.
- The recognition involves specific structural features of the tRNA molecule.

3. **Analyzing the Options**:
- **Option A: TψC loop** - This loop is involved in tRNA structure but is not primarily responsible for recognition by aminoacyl-tRNA synthetase.
- **Option B: DHL loop** - This loop is known to play a significant role in the recognition of tRNA by aminoacyl-tRNA synthetases.
- **Option C: Anticodon** - The anticodon is important for pairing with the mRNA codon but does not directly facilitate recognition by the synthetase.
- **Option D: AL loop** - This loop is also part of tRNA structure but is not the primary recognition site for aminoacyl-tRNA synthetase.

4. **Conclusion**:
- After analyzing the options, it is clear that the correct answer is **Option B: DHL loop**. This loop is specifically recognized by aminoacyl-tRNA synthetases during the charging of tRNA with its respective amino acid.

### Final Answer:
The tRNA recognizes aminoacyl-tRNA synthetase by the **DHL loop** (Option B).

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