In a double standed DNA, the sequence of nucleotides in one strand is 3' ATTCGCTAT 5'. What will be the complementary squence on the other strand ?

Options

A. a) 3' TAAGCGATA 5'
B. b) 5' TAAGCGATA 3'
C. c) 5' ATTCGCTAT 3'
D. d) 5' TAAGCGTTA 3'

Answer

To find the complementary sequence of the given DNA strand, we will follow these steps:

### Step-by-Step Solution:

1. **Identify the Given Strand**: The given DNA strand is 3' ATTCGCTAT 5'.

2. **Understand Base Pairing Rules**: In DNA, the base pairing rules are as follows:
- Adenine (A) pairs with Thymine (T)
- Thymine (T) pairs with Adenine (A)
- Cytosine (C) pairs with Guanine (G)
- Guanine (G) pairs with Cytosine (C)

3. **Write the Complementary Bases**: Starting from the 3' end of the given strand, we will write down the complementary bases:
- The first base (3' end) is A, which pairs with T.
- The second base is T, which pairs with A.
- The third base is T, which pairs with A.
- The fourth base is C, which pairs with G.
- The fifth base is G, which pairs with C.
- The sixth base is C, which pairs with G.
- The seventh base is T, which pairs with A.
- The eighth base is A, which pairs with T.
- The ninth base is T, which pairs with A.

4. **Construct the Complementary Strand**: Now, we will write the complementary bases in the correct order, starting from the 5' end to the 3' end:
- 5' TAAGCGATA 3'

5. **Final Answer**: The complementary sequence on the other strand is 5' TAAGCGATA 3'.