DNA Chemical Composition
A single strand of a DNA molecule consists of
a chain of nucleotide subunits (colored boxes).
Each nucleotide is made of the sugar deoxyribose
connected to an inorganic phosphate group, and
to one of four nitrogenous bases.
The phodiester
bonds that link the nucleotide subunits to each
other attach phosphate group of one nucleotide
to the deoxyribose sugar of the preceding nucleotide.
The DNA is situated in
the nucleus, organized into chromosomes. Every cell
must contain the genetic information and the DNA
is therefore duplicated before a cell divides (replication).
When proteins are needed, the corresponding genes
are transcribed into RNA (transcription).
The RNA
is first processed so that non-coding parts are
removed (processing) and is then transported out
of the nucleus (transport). Outside the nucleus,
the proteins are built based upon the code in the
RNA (translation).
|
