Which of the following m-RNA is translated completely :-
(A) 5' AUG UGA UUA AAG AAA 3'
(B) 5' AUG AUA UUG CCCC UGA 3'
(C ) 5' AGU, UCC AGA CUC UAA 3'
(D) 5' AUG UAC AGU AAC UAG 3'

Options

A. A and B
B. B and D
C. C and D
D. A and D

Answer

To determine which of the given mRNA sequences is translated completely, we need to identify the presence of start and stop codons in each sequence.

### Step-by-Step Solution:

1. **Understanding Codons**:
- Codons are sequences of three nucleotides in mRNA that correspond to specific amino acids or signal the termination of translation.
- The start codon is **AUG**, which codes for Methionine (MET) and initiates translation.
- Stop codons are **UAA**, **UAG**, and **UGA**. These do not code for any amino acid and signal the end of translation.

2. **Analyzing Each Option**:
- **Option (A)**: 5' AUG UGA UUA AAG AAA 3'
- Starts with **AUG** (start codon).
- Contains **UGA** (stop codon) as the second codon.
- **Conclusion**: Translation stops at UGA, so this mRNA is **not translated completely**.

- **Option (B)**: 5' AUG AUA UUG CCCC UGA 3'
- Starts with **AUG** (start codon).
- The sequence continues with AUA, UUG, and CCCC before reaching **UGA** (stop codon).
- **Conclusion**: Translation starts with AUG and continues until UGA, so this mRNA is **translated completely**.

- **Option (C)**: 5' AGU UCC AGA CUC UAA 3'
- Does not start with **AUG** (start codon).
- Contains **UAA** (stop codon) at the end.
- **Conclusion**: Since it does not start with AUG, this mRNA is **not translated completely**.

- **Option (D)**: 5' AUG UAC AGU AAC UAG 3'
- Starts with **AUG** (start codon).
- Contains **UAG** (stop codon) at the end.
- **Conclusion**: Translation starts with AUG and continues until UAG, so this mRNA is **translated completely**.

3. **Final Conclusion**:
- The mRNAs that are translated completely are **Option (B)** and **Option (D)**.

### Answer:
**(B) 5' AUG AUA UUG CCCC UGA 3' and (D) 5' AUG UAC AGU AAC UAG 3' are translated completely.**