The Language of The Cell


MAY 3rd, 1996
SCIENCE 10 AP

The cell is a complex and delicate system: It can be seen that the cell
is the stage where everyday functions such as molecule movement, protein
synthesis and tissue repair take place. All organelles within the cell are well
rehearsed in their operations, but an error on an organelles behalf, can send
the cell and it’s organelles into panic. The efficiency rate of the cell
plummets down to a low level. It does take some time for the dust to settle,
and once the scripts are memorized, the cell is now ready to begin it’s tasks
again.
Since the 19th Century, it was known that all living things, whether
they were plants or animals, were made up of cells. This whole idea has been
given credit to an English Physicist, Robert Hook (1635-1703), when he looked at
a thin slice of cork under powerful hand lens. Hook discovered a large number
of cells. Rudolf Virchow (1821-1902) propounded this idea, that the cell is a
basic structure and functional unit for all living organisms.
A cell can be a wide range of shapes and sizes, although most cells are
microscopic. Inside a cell membrane, a nucleus can be seen. The nucleus is the
control center of the cell. Between the nucleus and the membrane, there is a
polysaccharide matrix called the cytoplasm, where organelles can be found. The
organelles are attached to a framework. The cell’s cytoskeleton.
Every living cell has the ability to detect signals from it’s
environment. The signals are usually in the form of chemical molecules, that
the cell has learned to recognize. The cell decodes these molecules into
messages, and acts upon them. The cell has a “language”. Signals and messages
are carried by particles of matter that have a very low energy requirements.
There are many, many signals rumbling around the cell. It was thought that the
cell would confuse itself in all of that background signal noise. One defense
is available to this question. The cell’s decoding mechanisms are located
downstream from the receptors. They are based on complex chemical reactions
that take place in the cell membrane and control all the responses of the cell
to the messages it receives.
Neuropeptides and polypeptide hormones, are made up of complex
assemblies of amino acids, aligned in different sequences. In other cases, the
amino acids are slightly transformed, as this is the case with well known
transmitter substances such as epinephrine (adrenaline), dopamine and histamine.
Products made in the organelles within the cell, are sent to various
destinations, both in and out of the cell. The cell has what amounts to a
parcel delivery service, that is guided by “addresses,” by chemical “tags” or
labels. These labels generally consist of fairly simple molecules (often
sugars) attached to the product being forwarded and recognized by the structure
for which it is intended.
When a cell messes up on a delivery, which doesn’t happen very often, is
usually the result of a genetic defect. The “tag” on the product being
forwarded is usually mutated, therefore the receptor cannot recognize it.
Sometimes, the receptor is mutated, meaning that it does not recognize the
signal. The result of this is a botched cell. An example of this is a low
density lipoprotein receptor. If the lipoprotein fails to sequester and
internalize it’s signal (cholesterol), then cholesterol can no longer be
reincorporated in the cell, and it builds up in vessels, causing potentially
fatal conditions.
Three recent discoveries about the cell tell us that;

A) Each cell is not simply controlled by an accelerator and an inhibitor, and
the cell has the ability to recognize a great amount of signals. B) The number
of signals discovered in the body has increased tremendously. C) Signals within
the cell are not, as formerly believed, characteristic of an organ or function,
but they are all found in nearly all organs and are associated with nearly all
functions.

As mentioned earlier, signals are incredibly small, have low energy
requirements and weigh approximately one billionth of a gram. Scientists have
discovered new signals with the development of extremely effective chemical
methods that make it possible to purify them and elucidate their structure.
These advances and discoveries lead to a well understood field of protein
chemistry. One problem is that new signals are coming out everyday!
A point which should be stressed is that the universality of
communication implies that no signals are attached exclusively to one organ or
function. However, signals do not circulate unrestrictedly throughout the body.
Most signals are very versatile in the way that they can carry out all sorts of
assignments whether it