Question

If a DNA sequence was 5'-AATGCGGATTT-3' in one strand. What would be the sequence in the other strand? DNA chains are directional (like polypeptide chains) and anti-parallel. 5' and 3' are references to one end or the other.

5'-AATGCGGATTT-3'

3'-AATGCGGATTT-5'

3'-TTACGCCTAAA-5'

5'-TTACGCCTAAA-3'

3'-TTTAGGCGTAA-5'

Answer 1

DNA base pairing rules

* A with T – the purine base adenine always pair with the pyrimidine base thymine and vice versa

* C with G – the purine base cytosine always pair with the pyrimidine base guanine and vice versa

DNA strands are antiparellel. The given sequence direction is 5’ to 3’. Thus the direction of second strand is 3’ to 5’.

Answer : Option 3

3'-TTACGCCTAAA-5'