Given below are the steps of protein synthesis. Arrange them in correct sequence and select the correct option.
(i) Codon- anticodon reaction between mRNA and aminoacyl tRNA complex.
(ii) Attachment of mRNA and smaller sub-unit of ribosome.
(iii) Charging or aminoacylation of tRNA .
(iv) Attachment of larger sub-unit of ribosome to the mRNA-tRNA `_("Met")` complex.
(v) Linking of adjacent amino acids.
(vi) Formation of polypeptide chain.

Options

A. `(ii)to(i)to(iii)to(v)to(iv)to(vi)`
B. `(v)to(ii)to(i)to(iii)to(iv)to(vi)`
C. `(iii)to(ii)to(iv)to(i)to(v)to(vi)`
D. `(iii)to(ii)to(i)to(iv)to(v)to(vi)`

Answer

To arrange the steps of protein synthesis in the correct sequence, we need to understand the process clearly. Here are the steps provided in the question:

1. Codon-anticodon reaction between mRNA and aminoacyl tRNA complex.
2. Attachment of mRNA and smaller sub-unit of ribosome.
3. Charging or aminoacylation of tRNA.
4. Attachment of larger sub-unit of ribosome to the mRNA-tRNA `_("Met")` complex.
5. Linking of adjacent amino acids.
6. Formation of polypeptide chain.

### Step-by-Step Solution:

**Step 1: Charging of tRNA**
- The first step in protein synthesis is the charging or aminoacylation of tRNA. This involves the attachment of the correct amino acid to its corresponding tRNA molecule.

**Step 2: Attachment of mRNA and the smaller sub-unit of ribosome**
- After the tRNA is charged, the next step is the attachment of the mRNA to the smaller sub-unit of the ribosome. This is crucial for the initiation of translation.

**Step 3: Attachment of larger sub-unit of ribosome**
- Once the mRNA is bound to the smaller ribosomal sub-unit, the larger sub-unit of the ribosome attaches to form a complete ribosome ready for translation.

**Step 4: Codon-anticodon reaction**
- The charged tRNA then pairs with the mRNA at the ribosome through a codon-anticodon interaction. This ensures that the correct amino acid is added to the growing polypeptide chain.

**Step 5: Linking of adjacent amino acids**
- As the ribosome moves along the mRNA, adjacent amino acids are linked together through peptide bonds, facilitated by the ribosome.

**Step 6: Formation of polypeptide chain**
- Finally, this process continues until a complete polypeptide chain is formed, which will fold into a functional protein.

### Correct Sequence:
The correct sequence of steps is:
3 (Charging of tRNA) → 2 (Attachment of mRNA and smaller sub-unit of ribosome) → 4 (Attachment of larger sub-unit of ribosome) → 1 (Codon-anticodon reaction) → 5 (Linking of adjacent amino acids) → 6 (Formation of polypeptide chain).

### Final Answer:
The correct option is: **3 → 2 → 4 → 1 → 5 → 6**

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