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rom o ro e nsThe Central Dogma: Information ow fromNucleic Acids(DNA & RNA)to Amino Acids

(Protein)

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In Eukaryotes, gene expressionbegins in the nucleus with the process

of Transcription[DNA RNA] and concludes in the cytoplasm where

Translation[RNA rotein] takes place!

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DNA and RNA are polymers of nucleotides....

A nucleotide consists of" #$ a

phosphategroup, %$ a pentose&sugar

' Ribose or Deo(yribose$, and )$ anitrogen rich base(G,C, A,T or U

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*he Austrian biochemist, Erwin +hargaff ,

e(panded upon e-ene.s work and

reached two ma/or conclusions #$ *he

nucleotide composition of DNA -aries

among species0 %$ the amount of adenine

&A$ e1uals that of thymine &*$, and theamount of guanine &2$ e1uals that of

cytosine &+$! In other words, the total

amount of purines &A 3 2$ and the total

amount of pyrimidines &+3 *$ are usually

nearly e1ual! *his second ma/or conclusion

is now known as !Chargaff"s rule.!

Nucleic acids were disco-ered in #456 by

7wiss physiological chemist, 8riedrich

9iescher! :owe-er, it was another ;