N
N
N
H 2
O
O
O
P
O
O
O
O
N
N
N
N
O
N
N
O
H
O
O
P
O
O
O
O
O
P
O
O
O
O
O
P
O
O
O
O
P
O
O
O
O
N
N
NH 2
N
N
O
H
O
OH
O
P
O
O
O
NH 2
O
O
P
O
O
N
N
N
N
O
N
H 2
H
O
O
O
H
O
O
P
O
O
N
N
N
H 2
N
N
O
N
N
N
O
N H
NH 2
5'-end
3'-end
Base pairs
Sugar _ phosphate backbone
Sugar _ phosphate backbone
Hydrogen bonding
Adenine
Thymine
Cytosine
Guanine
Partial structure of DNA
While the sugar–phosphate backbone of DNA is completely regular, the
sequence of heterocyclic base pairs along the backbone can be of different
permutations. It is the precise sequence of base pairs that carries the genetic
information.
4.8.3 Nucleic acids and heredity
The genetic information of an organism is stored as a sequence of
deoxyribonucleotides strung together in the DNA chain. Three fundamental
4.8 NUCLEIC ACIDS
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