a phosphate group
- Each nucleotide consists of a five-carbon sugar to which is attached a phosphate group
and a nitrogenous base.
- This nucleic acid consists of four kind of nucleotides.
- The four differ only in their component base, which is adenine, guanine, cytosine or
uracil. Base nucleotide
Adenine (A) adenosine 5
/ monophosphate (AMP)
Guanine (G) guanosine 5
/ monophosphate (GMP)
Cytosine (C) cytidine 5
/ monophosphate (CMP)
Uracil (U) uridine 5
/ monophosphate (UMP)
Like DNA, RNA is assembled as a chain of nucleotides, but is usually singlestranded.
- The sugar molecule in the nucleotides that
make up DNA is a five-carbon
monosaccharide called deoxyribose ; a
similar sugar, called ribose is found in
RNA. The only difference between these
two sugars is that deoxyribose lacks an
oxygen atom on it number 2 carbon-hence
its name.
-Four different nitrogenous base are found
in DNA : adenine, guanine, cytosine and
thymine. RNA also contains adenine,
guanine and cytosine; but instead of
thymine, its fourth base is uracil.
- DNA is composed of two such chains
entwined in a double helix. RNA has a
single chain.