Asked by: Bassou Pratascience genetics
Why do purines bond with pyrimidines?
Last Updated: 27th June, 2020
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Subsequently, one may also ask, why do purines and pyrimidines bond together?
The molecular structure of both pyrimidinesandpurines allow them to only be able to bond witheachother and not within the group. Thymine(pyrimidine)andadenine (purine) both have two atomsthat can either providea H bond or receive it. Cytosine(pyr.) and guanine (pur.)can stablish three Hbonds.
Secondly, do pyrimidines form covalent bonds with purines? Pyrimidine-pyrimidine pairingsdonot occur because these relatively small moleculesdo notget close enough to form hydrogenbonds.Purine-purine links do notform becausethese bases are too large to fit in the spacebetween thepolynucleotide strands.
Hereof, what would happen if purines bond with purines?
Therefore, during pairing in DNA, twopurinescannot pair up together because there is not muchspace enoughbetween the two DNA helical strands to accommodatetwopurine groups, and thereby FOUR RINGS. Hence whileDNApairing, a purine always pairs up withapyrimidine.
What do purines pair with pyrimidines?
They pair together throughcomplementarypairing based on Chargaff's Rule (A::T andG::C). Thepurines in DNA are adenine and guanine, the sameas in RNA.The pyrimidines in DNA are cytosine and thymine;in RNA,they are cytosine and uracil.