Following are given sequences of mRNA Identify the one that will not undergo complete translation.

Options

A. 5 ' AUG UUC AGC UCG UGA 3'
B. 5' AUG CCA UAC GAC UAG 3'
C. 5 ' AUG UUA CUC GCG UAA 3'
D. 5' AUG AAC UAA CCA CUC 3'

Answer

To solve the question of which mRNA sequence will not undergo complete translation, we will analyze each given sequence for the presence of stop codons. Stop codons are specific sequences that signal the termination of translation, and they include UAG, UAA, and UGA.

### Step-by-Step Solution:

1. **Understand the Concept of Codons:**
- Codons are sequences of three nucleotides on mRNA that correspond to specific amino acids. There are 64 possible codons, out of which 61 code for amino acids and 3 are stop codons (UAG, UAA, UGA).

2. **Identify Stop Codons:**
- The stop codons are UAG, UAA, and UGA. If any of these codons appear in the middle of an mRNA sequence, translation will terminate prematurely.

3. **Analyze Each mRNA Sequence:**
- **Option A:** AUG, UUC, AGC, UCG, UGA
- The sequence ends with UGA, which is a stop codon. However, since it is at the end, translation can still occur completely before reaching this codon.

- **Option B:** AUG, CCA, UAC, GAC, UAG
- The sequence ends with UAG, which is a stop codon. Similar to Option A, translation can occur completely before reaching this codon.

- **Option C:** AUG, UUA, CUC, GCG, UAA
- The sequence ends with UAA, which is a stop codon. Again, translation can occur completely before reaching this codon.

- **Option D:** AUG, AAC, UAA, CCA, CUC
- The sequence contains UAA in the middle. This is a stop codon, and since it appears in the middle of the sequence, translation will terminate at this point, resulting in incomplete translation.

4. **Conclusion:**
- The sequence that will not undergo complete translation is **Option D**: AUG, AAC, UAA, CCA, CUC.

### Final Answer:
**Option D: AUG, AAC, UAA, CCA, CUC will not undergo complete translation.**