Chemistry Reference
In-Depth Information
The other one
D
-ribose
is found in
ribonucleic acids (RNA)
:
The sugars are in the furanose form. They are linked through the hydroxyl groups on carbons 3 and
5 as phosphate esters. The heterocyclic amine “bases” are attached at carbon 1, replacing the hydroxyl
group.
A sugar molecule with a base attached to it is referred to as a
nucleoside
:
NH
2
N
N
N
N
O
OH
OH
A nucleoside esterified with phosphoric acid is called a
nucleotide
:
NH
2
N
N
N
N
O
O
HO
P
OH
2
C
OH
OH OH
All the heterocyclic amines that occur in nucleic acids (DNA and RNA) are derivatives of either
pyrimidine or purine. These are:
NH
2
NH
2
O
H
CH
3
CH
3
N
N
N
N
N
N
O
O
O
H
H
H
cutosine
5-methylcytosine
thymine
