The cell - a living microcosmos?
||All living things are
made out of cells, from the simplest single cell amoeba
to large wales. The cell consists of many different parts,
with differing functions depending on which sort of cell
it is. For example, there are cells with and without
a nucleus. In cells with a nucleus this is where the
genetic information is stored.
DNA - the control code of the cell
|The genetic make-up
of the cell is stored in the nucleus in the form of DNA.
The DNA is a molecule which consists of two long chains
of so called nucleotides which are twisted around each
other in a double helix. The nucleotides consist of a
phosphate part, a sugar part and a nitrogen base. There
are four different nitrogen bases: adenine (A), guanine
(G), cytosine (C) and thymine (T), which belong in pairs,
so that A-T forms one pair and C-G the other.
DNA has the unique
property that it can copy itself. Since the base pairings
are unique it is possible to reconstruct the DNA-helix
from only one of the chains. Thanks to this, the cell
can divide and thereby multiply itself.
The DNA is in control of the life of the cell. Among
other things it controls the production of proteins
which are vital to the functionality of the cell.
In the last few years one has started
to use a number of instruments in molecular biology which
have initially been developed mainly for solid state physics.
For example the scanning electron microscope and the synchrotron
light technique. Today these methods play an important part
in determining the structure of biomolecules.
In the global Human Genome Project, HUGO,
one has made a map of all the genes in the human DNA.