A strand of DNA has following base sequence 3'-AAAAGTGACTAGTGA-5' On transcription, it produces an m-RNA which of the following anticodon of t-RNA recognizes the third codon of this mRNA :-

Options

A. AAA
B. CUG
C. GAC
D. CTG

Answer

To solve the question, we need to follow these steps:

### Step 1: Identify the DNA sequence
The given DNA sequence is:
3'-AAAAGTGACTAGTGA-5'

### Step 2: Transcribe the DNA to mRNA
To transcribe the DNA sequence into mRNA, we need to replace each base with its complementary RNA base:
- Adenine (A) pairs with Uracil (U) in RNA.
- Thymine (T) pairs with Adenine (A).
- Cytosine (C) pairs with Guanine (G).
- Guanine (G) pairs with Cytosine (C).

Thus, the transcription of the given DNA sequence would be:
- 3'-AAAAGTGACTAGTGA-5' (DNA)
- 5'-UUUUCACUGAUCACU-3' (mRNA)

### Step 3: Identify the codons in the mRNA
Now, we will break the mRNA sequence into codons (groups of three bases):
- First codon: UUU
- Second codon: UCA
- Third codon: CUG

### Step 4: Determine the anticodon for the third codon
The third codon is CUG. To find the corresponding tRNA anticodon, we need to find the complementary bases:
- C (Cytosine) pairs with G (Guanine)
- U (Uracil) pairs with A (Adenine)
- G (Guanine) pairs with C (Cytosine)

Thus, the anticodon for the third codon CUG is:
- GAC

### Step 5: Conclusion
The anticodon of tRNA that recognizes the third codon (CUG) of the mRNA is GAC.

### Final Answer:
The correct answer is GAC.

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