It allows enzymes such as RNA polymerase to attach the correct base to the new strand, and therefor conserve your genetic code (keep it the same).
Chargaff
transciption
Complimentary base pairing provides a means to replicate the genetic material.
Because if the pairing of the bases is incorrect then a mutation will form that can be silent or deadly .
adenine pairs with thymine, cytosine pairs with guanine
complimentary base-pairing
complimentary For example, if the DNA codon is GCA, the complimentary mRNA codon will be CGU, according to the base pairing rule.
The relationship of base pairing rules to the structure of DNA was observed by Rosalind Franklin. This observation was of purine pairing with pyrimidine that gives constant width to DNA structure.
DNA Polymerase
Base pairing refers to the pairing of complimentary nitrogen bases, either during DNA replication, or transcription and translation. In DNA, the bases adenine and thymine pair together, and guanine and cytosine pair together. In RNA, the base uracil takes the place of the base thymine. The bases that pair together are said to be complimentary to each other.
A complimentary codon is one that pairs with another codon according to the base pairing rule. For example, the DNA codon ATG is complimentary to the mRNA codon UAC.
mRNA makes a complimentary copy of the DNA molecule according to the base-pairing rule.