have several structures sticking out from them; hairlike pili.(function
that swim which have propellor like movements).used
This motor turns the long, helical.flagellum.propelling
through its environment.
Eukaryotic cells contain
a number of subcellular
spaces that are separated from the cytoplasm
by their own membranes.
These are called organelles,
which allow this cell to conduct specialized functions in specialized compartments.
One specialized organelle is the nucleus
containing the cell's DNA.
Many other fascinating parts
for cellular functions occur. The 'simpler' prokaryotes include; nuclear
reticulum, with its smooth and rough sides, Golgi
with its microtubules.(made
of actin, a specific
its protein filaments.comprising
three different thicknesses, like three gauges.(sizes).of
wire; macro filaments and intermediate sized filaments, mitotic
in the case of plants, added to these prokaryotes is cholorplast
containing chlorophyll), vacules,
hoarding of atoms to form molecules
with their compositional materials, amino
typically contain 50 to 3,000 amino acids),
acids with its parts, either ribose.(RNA).which
has a composition attached made from specified
combinations of its 4 bases, being adenine,
which similarly has adenine, cytidine, guanine and
Uracil replaces thymine.
This design allows for the code's meaning to remain consistent for both
RNA and DNA, while affecting the chemical mechanisms. It's like typing
a word with one letter in a different font, CAR as compared to car. The
information is clear, the meaning remains the same; yet the composition
varies, there being more chemicals.(ink,
if this was paper).in
in this one.(car
acid side chain gives an amino acid its particular character.
It is the particular shape of a
folded protein and the precise position of the different kinds of amino
acids that allow a protein to function in the various ways it does.
Complexity is evidenced in
the 'enzyme sacks' called bacterial
Here there are many levels of subcellular organization, for example; a
typical Escherichia coli cell is surrounded by two membranes enclosing
a periplasmic compartment that is used for acquiring and sorting nutrients
and wastes. The center of the cell contains DNA strands folded into a compact
forming a loosely defined compartment devoted to storage and use of genetic
information. The cytoplasm occupies the remaining portions of the cell
and is filled with ribosomes
and many different enzymes.
Many proteins are formed into complexes and thus enabled, subsequently
engage in many tasks. Some of these complexes combine several tasks to
increase efficiency. For example, molecules are delivered step to step
by the use of a flexible arm.
are created and folded and old ones are dispensed with, thanks to the functioning
chaperonins and proteasomes.
complex and requires highly efficient coding.
There is astonishing complexity
involved in how DNA polymerase.(a
and copying factory of genetic
information, telling the cell how to make polypeptides.
How does a cell know when
How does it select a specific gene from the thousands available? How does
the information get transferred from one 'polymer'
language to the other?
A cell makes an RNA
copy of a small portion of its DNA.(called
a process called
which codes for a protein.(a
special protein is manufactured using the DNA code).and
by a process termed as translation,
whereby the information in the RNA is used to produce a protein by latching
onto DNA at a binding site that it selects for utilization of a particular
The transcription of a gene
entails numerous decisions, one being where along the DNA chain to start.
This complicated, fascinating and mysterious
process involves balance of functioning, as when transcription is in
it becomes overwound, yet automatically corrects by cutting strands of
overwound DNA, passing the uncut strands through the cut strands and then
resealing the cut. Transcription stops when the RNA runs into a special
In DNA replication, a great
deal of effort is required in cell division to ensure the genetic information
be copied and handed down uncorrupted. Tasks are necessary to ensure accuracy
in the copying of the two parent strands and their separation and unknotting
as they form. Enzymes
repair DNA damaged
or other environmental insults. The enzyme complex polymerase
unbinds the nucleotide double helix of the DNA.