Asked by: Nato Gscheidlescience genetics
Why do purine and pyrimidine always pair together?
Last Updated: 18th March, 2020
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Also know, why does a purine always pair with a pyrimidine?
The molecular structure of both pyrimidinesandpurines allow them to only be able to bond with eachotherand not within the group. Thymine (pyrimidine)andadenine(purine) both have two atoms that can either providea Hbond or receive it. Cytosine (pyr.) and guanine (pur.) canstablishthree H bonds.
what is a purine and pyrimidine? Adenine and guanine belong to a class of compoundscalledpurines, while cytosine, thymine and uracil aretermedpyrimidines. The core of a purine is adouble-ringconstruct, one ring having five atoms and onepossessing six,whereas the smaller-molecular-weightpyrimidines have asingle-ring structure.
Similarly one may ask, why do purines bond with pyrimidines in DNA?
Purines (adenine and guanine) have twocarbonnitrogen ring bases. I think purines bond withpyrimidinesin the DNA ladder because adenine moleculesonly pairthymine molecules and guanine molecules only pair withcytosinemolecules. A and T bond with 2 hydrogen bonds, C andGbond with 3 hydrogen bonds.
What does purine pair with?
The rules of base pairing (ornucleotidepairing) are: A with T: the purineadenine (A)always pairs with the pyrimidine thymine (T) Cwith G: thepyrimidine cytosine (C) always pairs with thepurineguanine (G)