Asked by: Nato Gscheidle
science genetics

Why do purine and pyrimidine always pair together?

Last Updated: 18th March, 2020

These nucleotides are complementary—theirshape allows them to bond together with hydrogenbonds. Inthe C-G pair, the purine (guanine) has threebindingsites, and so does the pyrimidine (cytosine).Thehydrogen bonding between complementary bases is whatholdsthe two strands of DNA together.

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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)

Related Question Answers

Eresvita Omodei


What does cytosine pair with?

Each nucleotide base can hydrogen-bond with aspecificpartner base in a process known as complementarybasepairing: Cytosine forms three hydrogen bondswithguanine, and adenine forms two hydrogen bonds with thymine.Thesehydrogen-bonded nitrogenous bases are often referred to asbasepairs.

Malkeet Scheunpflug


What term means base pairing?

Base pairing is simple. There are fourbasepairs, Adenine, Thymine, Cytosine, and Guanine. Adeninealways paiswith Thymine, while Cytosine always pairs with Guanine.There aretwo hydrogen bonds between a and t and there are threebetween c andg.

Hommad Asendorf


What two bases are purines?

Purines and Pyrimidines arenitrogenousbases that make up the two different kindsofnucleotide bases in DNA and RNA. Thetwo-carbonnitrogen ring bases (adenine and guanine)arepurines, while the one-carbon nitrogen ringbases(thymine and cytosine) arepyrimidines.

Monserrate Ibaeta


Priscilo Loro


What do base pairs do?

Base pairs occur when nitrogenousbasesmake hydrogen bonds with each other. Each basehas aspecific partner: guanine with cytosine, adenine with thymine(inDNA) or adenine with uracil (in RNA). The hydrogen bonds areweak,allowing DNA to 'unzip'. This lets enzymes replicatetheDNA.

Jacqualine Sourav


How do the 4 bases of DNA pair up?

Attached to each sugar ring is a nucleotidebase,one of the four bases Adenine (A), Guanine (G),Cytosine(C), and Thymine (T). The hydrogen bonding betweencomplementarybases holds the two strands of DNAtogether. Hydrogenbonds are not chemical bonds.

Rkiya Girling


Which part of the nucleic acid building blocks are the same in DNA and RNA?

The two main types of nucleic acids are DNAandRNA. Both DNA and RNA are made from nucleotides,eachcontaining a five-carbon sugar backbone, a phosphate group,and anitrogen base. DNA provides the code for the cell'sactivities, while RNA converts that code into proteinstocarry out cellular functions.

Acacia Kergoat


What holds the nitrogen bases together in DNA?

Strands of DNA are made of the sugar andphosphateportions of the nucleotides, while the middle parts aremade of thenitrogenous bases. The nitrogenous baseson the twostrands of DNA pair up, purine with pyrimidine (Awith T, Gwith C), and are held together by weakhydrogenbonds.

Fidanka Bird


What is the composition of the backbone of DNA?

It has an alternating chemical phosphate andsugarbackbone, making the 'sides' of the ladder.(Deoxyribose isthe name of the sugar found in the backbone ofDNA.) Inbetween the two sides of this sugar-phosphatebackbone arefour nitrogenous bases: adenine (A), thymine(T), cytosine (C), andguanine (G).

Dorotha Lucio


What are the two pyrimidines?

Pyrimidines contains one carbon-nitrogen ringandtwo nitrogen atoms.They have low melting point. Bluespheresare Nitrogen atoms and Pyrimidines is a one ringmolecule.Two Purines are Adenine and Guanine. TwoPyrimidinesare Thymine and Uracil.

Nahara Cataluña


Is uracil a purine?

The other type is called a purine.Uracil,a nitrogenous base found in RNA, is a pyrimidine. Twootherpyrimidines are cytosine and thymine. Thymine is only foundinDNA.

Aretha De Porras


Where does purine synthesis occur?

1 Answer. Correct, all but one step inpyrimidinesynthesis occurs in the cytosol, and purinesynthesisoccurs in the cytosol only. Nucleotides freely diffusethroughnuclear pores but are actively transported throughmitochondrialmembranes via embedded membrane transportproteins(i.e.