Which step of translation does not consume high energy `PO_4` bond ?

Options

A. Translocation
B. tRNA activation
C. Amino acid activation
D. Peptydyl transferase reaction

Answer

**Step-by-Step Solution:**

1. **Understanding Translation**: Translation is the process by which proteins are synthesized from messenger RNA (mRNA). It involves several steps, including initiation, elongation, and termination.

2. **Identifying the Steps of Translation**: The main steps involved in translation are:
- tRNA charging (amino acid activation)
- Peptidyl transferase reaction
- Translocation

3. **Analyzing Each Option**:
- **Option A: Translocation**: This step involves the movement of the ribosome along the mRNA and generally consumes energy in the form of GTP, but it does not directly involve the consumption of a high-energy phosphate bond (like ATP).
- **Option B: tRNA**: This refers to the transfer RNA that carries amino acids to the ribosome. The charging of tRNA with amino acids consumes ATP, which involves a high-energy phosphate bond.
- **Option C: Amino Acid Activation**: This step involves the attachment of an amino acid to its corresponding tRNA and requires ATP, thus consuming a high-energy phosphate bond.
- **Option D: Peptidyl Transferase Reaction**: This is the reaction where the peptide bond is formed between adjacent amino acids. This step does not consume a high-energy phosphate bond.

4. **Conclusion**: The step of translation that does not consume a high-energy phosphate bond is the **Peptidyl Transferase Reaction** (Option D).

**Final Answer**: Peptidyl Transferase Reaction (Option D)

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