Watson-crick base pairing: Difference between revisions

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[[Image:Watson_n_crick.jpg|James Watson and Francis Crick]]
[[Image:Watson n crick.jpg|left|James Watson and Francis Crick]] [[Image:BASE PAIRS.png|right|199x253px|Figure 1.1 A-T and G-C base pairs]]  


DNA consists of two types of bases namely; [[Purine|Purines]] and [[Pyrimidine|Pyrimidines]]. There are two types of Purines: [[Adenine|Adenine]] and [[Guanine|Guanine]] as well as two types of Pyrimidines: [[Cytosine|Cytosine]] and [[Thymine|Thymine ]]. In the Watson-Crick DNA base pairing model a Purine always binds with a Pyrimidine, however, each purine binds to one particular type of pyrimidine.  
DNA consists of two types of bases namely; [[Purine|purines]] and [[Pyrimidine|pyrimidines]]. There are two types of purines: [[Adenine|adenine]] and [[Guanine|guanine]] as well as two types of Pyrimidines: [[Cytosine|cytosine]] and [[Thymine|thymine]]. In the Watson-Crick DNA base pairing model a purine always binds with a pyrimidine, however, each purine binds to one particular type of pyrimidine.  


Adenine(A) binds to Thymine(T) whilst, Guanine(G) binds to Cytosine(C); although in RNA&nbsp;Unracil (U)&nbsp;is substituted for Thymine(T). This base pairing is referred to as complementary, hence the base pairs are called complementary [[Base pairs|base pairs]].<ref>Hartl D., Ruvolo M. (2012) Genetics; Analysis of Genes and Genomes, 8th edition, Burlington: Jones and Barlett.</ref>&nbsp;&nbsp;The base pairs are bound by [[Hydrogen bonds|Hydrogen bonds]], although the number of H-bonds differs between base pairs. G-C base pairs are bound by three (3) Hydrogen bonds whilst, A-T base pairs are bound by two (2) Hydrogen bonds as illustrated by Figure 1.1 below.  
Adenine (A) binds to thymine (T) whilst, guanine (G) binds to cytosine (C); although in RNA&nbsp;unracil (U)&nbsp;is substituted for thymine (T). This base pairing is referred to as complementary, hence the base pairs are called complementary [[Base pairs|base pairs]]&nbsp;<ref>Hartl D., Ruvolo M. (2012) Genetics; Analysis of Genes and Genomes, 8th edition, Burlington: Jones and Barlett.</ref>.&nbsp; The base pairs are bound by [[Hydrogen bonds|hydrogen bonds]], although the number of H-bonds differs between base pairs. G-C base pairs are bound by three (3) hydrogen bonds whilst, A-T base pairs are bound by two (2) hydrogen bonds as illustrated in the figure on the right.  


&nbsp;&nbsp;&nbsp;[[Image:BASE PAIRS.png|199x253px|Figure 1.1 A-T and G-C base pairs]]&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  
=== Importance&nbsp;&nbsp;&nbsp;&nbsp; ===


==== Importance&nbsp;&nbsp;&nbsp;&nbsp;  ====
Watson-Crick base&nbsp;pairing is of very great importance as it&nbsp;is a deciding factor in [[Semi-conservative replication|DNA&nbsp;Replication]]&nbsp;<ref name="null">Genetic Science Learning Center (2011) Build a DNA Molecule. Learn.Genetics. Available at: http://learn.genetics.utah.edu/content/begin/dna/builddna/. [Last assessed: 26/11/2011] University of Utah</ref>. It ensures that pairs form between complementary bases only. The formation of base pairs between two non-complementary bases&nbsp;results in&nbsp;[[Mutations|gene mutations]] which can be detrimental to development of an organism.  
 
Watson-Crick base&nbsp;pairing is of very great importance as it&nbsp;is a deciding factor in [[Semi-conservative replication|DNA&nbsp;Replication]].<ref name="null">Genetic Science Learning Center (2011) Build a DNA Molecule. Learn.Genetics. Available at: http://learn.genetics.utah.edu/content/begin/dna/builddna/. [Last assessed: 26/11/2011] University of Utah</ref> It ensures that pairs form between complementary bases only. The formation of base pairs between two non-complementary bases&nbsp;results in&nbsp;[[Mutations|gene mutations]] which can be detrimental to development of an organism.  


=== References  ===
=== References  ===


<references />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
<references />&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

Revision as of 21:12, 26 November 2011

James Watson and Francis Crick
James Watson and Francis Crick
Figure 1.1 A-T and G-C base pairs
Figure 1.1 A-T and G-C base pairs

DNA consists of two types of bases namely; purines and pyrimidines. There are two types of purines: adenine and guanine as well as two types of Pyrimidines: cytosine and thymine. In the Watson-Crick DNA base pairing model a purine always binds with a pyrimidine, however, each purine binds to one particular type of pyrimidine.

Adenine (A) binds to thymine (T) whilst, guanine (G) binds to cytosine (C); although in RNA unracil (U) is substituted for thymine (T). This base pairing is referred to as complementary, hence the base pairs are called complementary base pairs [1].  The base pairs are bound by hydrogen bonds, although the number of H-bonds differs between base pairs. G-C base pairs are bound by three (3) hydrogen bonds whilst, A-T base pairs are bound by two (2) hydrogen bonds as illustrated in the figure on the right.

Importance    

Watson-Crick base pairing is of very great importance as it is a deciding factor in DNA Replication [2]. It ensures that pairs form between complementary bases only. The formation of base pairs between two non-complementary bases results in gene mutations which can be detrimental to development of an organism.

References

  1. ↑ Hartl D., Ruvolo M. (2012) Genetics; Analysis of Genes and Genomes, 8th edition, Burlington: Jones and Barlett.
  2. ↑ Genetic Science Learning Center (2011) Build a DNA Molecule. Learn.Genetics. Available at: http://learn.genetics.utah.edu/content/begin/dna/builddna/. [Last assessed: 26/11/2011] University of Utah

                             

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