During the translation process , the ATP molecule is required for

Options

A. Association of 50S subunit of the ribosome with the initiation complex .
B. Binding of 305 subunit of the ribosome with mRNA
C. Association of 30S - mRNA with formyl - met - tRNA .
D. Charging of tRNA

Answer

**Step-by-Step Solution:**

1. **Understanding Translation**:
- Translation is the process of protein synthesis that occurs in the cytoplasm of the cell. It involves decoding the information carried by messenger RNA (mRNA) to synthesize proteins.

2. **Role of ATP in Translation**:
- ATP (adenosine triphosphate) is a crucial energy molecule in cellular processes. During translation, ATP is specifically required for the charging of tRNA.

3. **Charging of tRNA**:
- The charging of tRNA is the first step in translation where an amino acid is attached to its corresponding tRNA molecule. This process is essential for the incorporation of the correct amino acid into the growing polypeptide chain.

4. **Mechanism of Charging**:
- The amino acid reacts with ATP, leading to the formation of an aminoacyl-AMP complex. This reaction releases pyrophosphate (PPi) and is catalyzed by an enzyme called aminoacyl-tRNA synthetase.
- The charged tRNA (aminoacyl-tRNA) is then formed when the amino acid is transferred from the aminoacyl-AMP to the tRNA molecule.

5. **Conclusion**:
- Among the options provided, the correct answer is D. Charging of tRNA, as ATP is specifically required for this process during translation.