Which of the following is not correct about translation

Options

A. It starts with UAG
B. Stopped at termination codon
C. Based on operon model
D. Occurs in nucleus

Answer

**Step-by-Step Solution:**

1. **Understand the Process of Translation**: Translation is the process by which proteins are synthesized from messenger RNA (mRNA). It involves the decoding of the mRNA sequence into a polypeptide chain (protein) with the help of transfer RNA (tRNA) and ribosomal RNA (rRNA).

2. **Identify the Start Codon**: The translation process begins with a specific codon on the mRNA that signals the start of protein synthesis. The most common start codon is AUG, which codes for the amino acid methionine. GUG can also serve as a start codon in some cases.

3. **Evaluate the Statements**: The question asks which statement is NOT correct about translation.
- **Statement 1**: "It starts with UAG." This is incorrect because UAG is a stop codon, not a start codon.
- **Statement 2**: "Stops at the termination codon." This is correct; translation stops at one of the three stop codons (UAA, UAG, UGA).
- **Statement 3**: "It is based on the operon model." This is somewhat misleading as the operon model primarily describes gene regulation in prokaryotes, not translation directly.
- **Statement 4**: "It occurs in the nucleus." This is incorrect because translation occurs in the cytoplasm, not in the nucleus.

4. **Determine the Incorrect Statements**: Based on the analysis:
- Statement 1 (starts with UAG) is incorrect.
- Statement 4 (occurs in the nucleus) is also incorrect.

5. **Conclusion**: Since the question asks for the statement that is NOT correct about translation, both Statement 1 and Statement 4 are incorrect. However, if the question requires only one answer, Statement 1 is the most explicitly incorrect regarding the initiation of translation.

**Final Answer**: The statement that is not correct about translation is: "It starts with UAG."

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