If the base sequence in DNA is 5' AAAA 3' then the bases sequence in m-RNA is :-

Options

A. 5' UUUU 3'
B. 3' UUUU 5'
C. 5' AAAA 3'
D. 3' TTTTT 5'

Answer

To determine the base sequence in mRNA from the given DNA sequence, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the DNA Sequence**: The given DNA base sequence is 5' AAAA 3'.

2. **Understand Transcription**: During transcription, the DNA sequence is used as a template to synthesize mRNA. The mRNA is complementary to the DNA template strand.

3. **Determine the Complementary Base Pairing**:
- In DNA, adenine (A) pairs with thymine (T), and cytosine (C) pairs with guanine (G).
- However, in RNA, adenine (A) pairs with uracil (U) instead of thymine (T).

4. **Reverse the DNA Sequence**: Since mRNA is synthesized in the 5' to 3' direction, we first consider the complementary sequence in the 3' to 5' direction. The complementary bases to the DNA sequence 5' AAAA 3' would be:
- A (from DNA) pairs with U (in RNA)
- Thus, the complementary sequence in the 3' to 5' direction would be 3' UUUU 5'.

5. **Write the mRNA Sequence**: Since mRNA is synthesized in the 5' to 3' direction, we reverse the sequence obtained in the previous step:
- The final mRNA sequence is 5' UUUU 3'.

### Final Answer:
The base sequence in mRNA is **5' UUUU 3'**.

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