Watson-crick base pairing
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| + | [[Image:Watson_n_crick.jpg|James Watson and Francis Crick]] | ||
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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 Unracil (U) is substituted for Thymine(T). This base pairing is referred to as complementary, hence the base pairs are called complementary [[ | + | 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|base pairs]].<ref>Hartl D., Ruvolo M. (2012) Genetics; Analysis of Genes and Genomes, 8th edition, Burlington: Jones and Barlett.</ref> 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. |
[[Image:BASE PAIRS.png|199x253px|Figure 1.1 A-T and G-C base pairs]] | [[Image:BASE PAIRS.png|199x253px|Figure 1.1 A-T and G-C base pairs]] | ||
Revision as of 19:48, 26 November 2011
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 by Figure 1.1 below.
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
- ↑ Hartl D., Ruvolo M. (2012) Genetics; Analysis of Genes and Genomes, 8th edition, Burlington: Jones and Barlett.
- ↑ 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
