Describe complementary base pairing between DNA with DNA and DNA with RNA

Explanation:

The complementarity of nitrogenous bases consists of the union of a purine base and a pyrimidine base, allowing the bonding between two strands of a nucleic acid.

In DNA the purines are adenine (A) and guanine (G), while the primidines are cytosine (C) and thymine (T).

In RNA the purines are adenine and guanine, the pyrimidines being cytosine and uracil (U), since thymine is not found in RNA.

DNA with DNA      DNA with RNA

     A=T                           A=U

     C≡G                          C≡G

Base pairing in DNA —DNA with DNA— is important in holding its two strands together, as well as in the replication process, which is carried out according to base complementarity.

DNA-RNA base pairing is observed during transcription where a purine base from the DNA template strand allows the incorporation of a pyrimidine into RNA, while a pyrimidine from DNA is complemented by a purine in RNA.