If one starand of double stranded DNA, consists of the sequence `3'ATTCGTAC-5',` then the complementary sequence must be -

Options

A. `5'-UAGCAUG-3'`
B. `3'-TAGCATG-5'`
C. `5'-TAGCATG-3'`
D. `5'-TAGCATG-3'` in the reverse direction

Answer

To determine the complementary sequence of the given DNA strand `3' ATTCGTAC 5'`, we need to follow these steps:

### Step-by-Step Solution:

1. **Identify the Base Pairing Rules**: In DNA, the bases pair in a specific way:
- Adenine (A) pairs with Thymine (T)
- Cytosine (C) pairs with Guanine (G)

2. **Write Down the Given Strand**: The given strand is `3' ATTCGTAC 5'`.

3. **Complementary Base Pairing**:
- For each base in the given strand, write down its complementary base:
- A (from `ATTCGTAC`) pairs with T
- T pairs with A
- T pairs with A
- C pairs with G
- G pairs with C
- T pairs with A
- A pairs with T
- C pairs with G

4. **Construct the Complementary Strand**: Based on the pairs:
- A → T
- T → A
- T → A
- C → G
- G → C
- T → A
- A → T
- C → G

This gives us the sequence: `5' TAAGCATG 3'`.

5. **Indicate the Direction**: Since DNA strands are anti-parallel, the complementary strand should be written in the 5' to 3' direction. Therefore, the final complementary sequence is `5' TAGCATG 3'`.

### Final Answer:
The complementary sequence to `3' ATTCGTAC 5'` is `5' TAGCATG 3'`.

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