Compare the statements A and B
Statement A : A monocistronic mRNA can produce several types of polypeptide chains.
Statement B: The terminator codon is present on the mRNA.
Select the correct description:

Options

A. Both the statements A and B are wrong
B. Statement A is correct and B is wrong
C. Statement A is wrong and B is correct
D. Both the statements A and B are correct

Answer

To compare the statements A and B, let's analyze each statement step by step.

### Step 1: Analyze Statement A
- **Statement A**: "A monocistronic mRNA can produce several types of polypeptide chains."
- **Definition of Monocistronic mRNA**: Monocistronic mRNA contains only one cistron (a segment of DNA that encodes a single polypeptide). This means that it can only code for one specific polypeptide chain.
- **Conclusion for Statement A**: Since a monocistronic mRNA can only produce one type of polypeptide, this statement is **incorrect**.

### Step 2: Analyze Statement B
- **Statement B**: "The terminator codon is present on the mRNA."
- **Definition of Terminator Codon**: Terminator codons (like UAA, UAG, UGA) signal the end of translation. They are indeed present on the mRNA and indicate where the protein synthesis should stop.
- **Conclusion for Statement B**: Since terminator codons are present on mRNA, this statement is **correct**.

### Step 3: Compare the Statements
- From the analysis, we found that:
- Statement A is **incorrect**.
- Statement B is **correct**.

### Final Conclusion
Based on the analysis, the correct description is that Statement A is wrong and Statement B is correct. Therefore, the answer is that **Statement A is incorrect and Statement B is correct**.