Purines and pyrimidines

Chapter 12 Purines and pyrimidines



Chapter contents


Nucleosides and nucleotides 89

Metabolism of purines and pyrimidines 91

DNA and RNA 92

Purines and pyrimidines are known as nitrogenous bases. The two groups have different features (Figure 12.1):


• Purines: a six-membered and a five-membered nitrogen-containing ring fused together.

• Pyrimidines: a six-membered nitrogen-containing ring.

image

Figure 12.1 The structure of purines and pyrimidines.


These nitrogenous bases are crucial not only to the storage and transmission of genetic information, but also as a means of storing mobile energy. They can be synthesized in the body from basic components. The degraded bases can be salvaged and reused (see Chapter 37 ‘Metabolic disorders’, p. 295).



Nucleosides and Nucleotides


When a sugar is added to a nitrogenous base, a nucleoside is formed (Figure 12.2).


image

Figure 12.2 The basic structure of nucleosides and their inclusion in the nucleotide structures of RNA and DNA.

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Related posts:

  1. Metabolism
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  4. The nervous system

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Jul 22, 2016 | Posted by in PHARMACY | Comments Off on Purines and pyrimidines

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