Our sense organs 45

total anatomy and physiology of a human being,
but also our numerous predispositions and gifts.
For example, musical ability, aggressiveness, or
language aptitude. Are the non-material characteristics
of people, for example, the ability to
love, or experience joy, in fact reducible to being
described by a nucleotide sequence? Here we still
face major scientific mysteries.
Information processing: Our 30,000 genes provide
exact instructions to each cell for manufacturing
everything required for it to carry out the
role for which it is programmed; whether hormones,
enzymes, mucus, sebum, the weapons of
the immune system, or the impulses in the nerve
cells of the central nervous system.
One might well ask at this point: How is this
information decoded, and how are these abstract
“words” translated into concrete protein molecules?
This never-ending process takes place
inside an unimaginably small space, namely
within the cells, each measuring only a few hundredths
of a millimetre. Special protein molecules
locate a particular piece of information – a gene –
copy it, and prepare a messenger, a chemical relative
of DNA called messenger-RNA. This mRNA
then travels from the control centre in the nucleus
out into the cytoplasm, to the ribosomes.
These small granular bodies are where protein
synthesis takes place. When these RNA messengers
arrive here, they specify the sequence in
which the 20 types of amino acids, the building
blocks of all proteins, are to be assembled. Protein
molecules are constructed here “block by
block”, just as a house is built brick by brick; they
are subsequently dispatched to carry out their
various vital functions.
The next important step, namely the formation of
specific structures like cells and organs from
these protein molecules, is very complex, and is
not yet fully understood. But we do know that it
is somehow encoded in our genes * , and it largely
determines what we are. Our genes ensure that
we become human beings rather than animals.
Our gender, the colour of our eyes, skin and hair,
and to a great extent our size, are all determined
by our personal genome. It sets parameters for
our intelligence and, to a large extent, determines
our never-to-be-repeated unique personality. All
these patterns are set at the precise moment in
which the male chromosomes in a sperm cell
meet up with those of a female egg cell (ovum).
The moment of fertilisation truly is the starting
point of our life.
A comparison: Each of our approximately 100
million million (10 14 ) cells has the following main
components: a cell membrane, many pores and
channels in this membrane, many mitochondria
for regulating the flow of energy, many ribosomes
which translate genetic information into
proteins, and a nucleus containing the genetic
information in the form of DNA.
Nowadays many people are familiar with the
parts of a personal computer (PC), like hard disk,
read/write head, interface, and network card. To
explain the performance and complex functioning
of a biological cell, Zoltán Takács, a biophysicist,
compared the processing and storage of information
in a cell with what happens inside a
computer. If a cell in simplified form is regarded
as a computer, we have the following analogies:
– The cell membrane would be the computer
housing, but it is only 10 nanometres thick
(= one hundred thousandth of a millimetre).
– The pores and channels are the interfaces.
– The mitochondria comprise 800 network
cards.
– A ribosome would be a central processing
unit (CPU), but a biological cell has more than
six million CPUs.
– The nucleus would correspond to a hard drive.
There would then be 23 different hard disks
(= chromosomes), each of which has its own
backup disk. The storage capacities of these
23 disks add up to about 1 Gigabyte. Biological
“hard disks” are actually not hard, but can perhaps
be regarded more like ”floppy disks”; the
46 strands of DNA do not rotate around
a fixed spindle, but occur as loose clusters in
the nucleus.
– The diameter of this biological computer is
about 20 micrometres (= two hundredths of
a millimetre).
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