Nucleosides and Nucleotides

	Back to Home
Deoxyribosenucleic Acid - DNA Nucleic Acids History of Nucleic Acids Genetic Material of Organisms Structure of DNA Nucleosides and Nucleotides Nucleosides of RNA and DNA Ribonucleosides and Ribonucleotides Deoxyribonucleosides and Deoxyribonucleotides Unusual Bases in DNA

Nucleosides and Nucleotides

	Nucleosides and Nucleotides -A sugar molecule and a nitrogenous base form a nucleoside, and a nucleoside plus a phosphate group form a nucleotide.In other words a nucleoside is a base-sugar combination and a nucleotide is a nucleoside phosphate. The nucleotides of RNA are called ribonucleotides, and a nucleoside and of DNA dexoyribonucleotides.
Ribonucleotides contain the sugar ribose and deoxyribonuc1eotides the sugar deoxyribose.The ribose in a nucleoside has free hydroxyl groups on carbons 2'. 3' and 5'. The phosphate can be attached at aw of these positions. Although all the three nucleoside monophosphate have been found, the most commonly occuring ones are 5' -phosphates and 3' -phosphates.Deoxyribose has only two hydroxyl groups (on carbons 3' and 5') and can thus form only two deoxyribonucleotides, the 3' and the 5' phosphate derivatives.
The nucleosides are usually abbreviated as A, T, G or C, with as a prefix for deoxynucleosides (e. g. dG- is the abbreviation for deoxyguanosine) . The nucleotides involved in metabolic reactions are generally 5' -phosphate esters of nucleosides. When no number appears before the abbreviation the 5' - ester is implied.
Thus- AMP, ADP and ATP are abbreviations for adenosine-5' -monophosphate, adenosine-5' -diphosphate and adenosine-5' -triphosphate, respectively.

	Back to Home
Single Stranded DNA Localization of Nucleic Acids Forms of DNA Characteristics of Different Forms of DNA RL Helix and Z-DNA Palindromic DNA Repetitive DNA (Satellite DNA) Satellite DNA of Drosophila Virilis