How many coded nitrogen bases are present in m-RNA from which a polypeptide chain with 60 amino acids is formed in bacteria cells, (including nonsense codon)?

Options

A. 200
B. 60
C. 180
D. 183

Answer

To determine how many coded nitrogen bases are present in mRNA from which a polypeptide chain with 60 amino acids is formed in bacterial cells (including nonsense codon), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Number of Amino Acids**:
- We are given that the polypeptide chain consists of 60 amino acids.

2. **Calculate the Number of Codons for Amino Acids**:
- Each amino acid is coded by a codon, and each codon consists of 3 nitrogen bases (nucleotides).
- Therefore, for 60 amino acids, the number of codons required is:
\[ \text{Number of codons} = 60 \text{ amino acids} \]

3. **Calculate the Total Number of Nitrogen Bases for Amino Acids**:
- Since each codon consists of 3 nitrogen bases, the total number of nitrogen bases for the amino acids is:
\[ \text{Total nitrogen bases for amino acids} = 60 \times 3 = 180 \]

4. **Include the Stop Codon**:
- In addition to the codons for the amino acids, there is 1 stop codon that signals the end of translation.
- The stop codon also consists of 3 nitrogen bases.
- Therefore, we need to add the nitrogen bases from the stop codon:
\[ \text{Total nitrogen bases including stop codon} = 180 + 3 = 183 \]

5. **Final Answer**:
- The total number of coded nitrogen bases present in mRNA, including the stop codon, is 183.

### Conclusion:
The correct answer is **D. 183**.