Question

Explain the base pairing rules of DNA. Provide an example of a strand of DNA with its complementary pair.

Answer 1

Answer:

Two DNA strands are complementary in their nucleotide sequences. A purine base in one DNA strand always pairs with a pyrimidine base of another DNA strand.

Explanation:

The base-pairing rules state that a purine base always pairs with a pyrimidine base in DNA. This is why adenine base makes two hydrogen bonds with thymine and cytosine makes three hydrogen bonds with guanine. Due to this complementary base pairing, the nucleotide sequence of the DNA template is complementary to that of the newly formed DNA strand during the process of replication.

For example, a DNA template strand with sequence 5' AATTCCGG 3' would replicate into the daughter DNA strand with the sequence 3' TTAAGGCC 5'.