The t RNA molecules with the following anti codons do not exist in cells

Options

A. AUU, ACU, AUC
B. AUA, ACA AUC
C. AAU, ACU, ACC
D. ACC, AUC, ACU

Answer

To solve the question regarding which tRNA molecules with specific anticodons do not exist in cells, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Role of tRNA**: tRNA (transfer RNA) is a type of RNA that helps in the translation process of protein synthesis. Each tRNA molecule carries a specific amino acid and has an anticodon that pairs with the corresponding codon on mRNA.

2. **Identify Anticodons**: The question provides specific anticodons: AUU, ACU, and AUC. We need to determine if tRNA molecules corresponding to these anticodons exist in cells.

3. **Check Codon-Anticodon Pairing**: Anticodons are complementary to codons. For example, if the codon on mRNA is AUA, the corresponding anticodon on tRNA would be UAU. We need to analyze the provided anticodons to see if they correspond to existing codons.

4. **Analyze Each Anticodon**:
- **AUU**: This anticodon pairs with the mRNA codon UAA, which is a stop codon. Therefore, there is no tRNA with the anticodon AUU because it would not have an amino acid to carry.
- **ACU**: This anticodon pairs with the mRNA codon UGA, which is also a stop codon. Similar to AUU, there is no tRNA with the anticodon ACU.
- **AUC**: This anticodon pairs with the mRNA codon GAU, which codes for the amino acid aspartic acid. Therefore, tRNA with the anticodon AUC does exist.

5. **Conclusion**: Since AUU and ACU correspond to stop codons and do not have associated tRNA molecules, the answer to the question is that tRNA molecules with the anticodons AUU and ACU do not exist in cells.

### Final Answer:
The tRNA molecules with the following anticodons do not exist in cells: AUU and ACU.

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