FREE ESSAY ON BACTERIA

BACTERIA

As hard as it is to believe, bacteria (also known to scientists as Bacillus, thuringensis)
are everywhere; on your hands, on door handles, there's even thousands bacteria on the
period at the end of this sentence (That's how small they are). Bacteria have been around
for about 3.5 billion years. They were the first life forms on earth and more numerous
then any other species we know of. Yet, while they are extremely common, they are also
very small. Bacteria can only be seen with microscopes and are usually less then one
micron (0.00002 inches) in length. Before I can explain how bacteria affect our world,
you need to know more about them. Basically, bacteria are numerous, unicellular organisms
that don't contain a nucleus and consist of a capsule and a cell membrane made of
peptidoglycan (that's a protein-sugar molecule). Like all cells, bacteria contain DNA,
but the DNA in bacteria is different then other organisms, see it's arranged in a single
circular chromosome while most cells have several rod shaped chromosomes. Some bacteria
also have flagella. This assists the bacteria in moving by beating in a propeller-like
motion. 
Bacteria can be classified in many different ways. Because of their simple cells
structure they fit into the Moneran kingdom. Within that everything is a prokaryote
(single celled organism that does not contain a nucleus) so the Moneran kingdom is
sometimes called the Prokaryotae kingdom. (Confusing system right?) Bacteria are also
sometimes classified as gram negative or gram positive depending on the composition of
their cell walls. There are also bacteria that need oxygen called aerobic bacteria and
bacteria that don't need oxygen called anaerobic bacteria. Since there are so many
different types of bacteria it's hard to figure out how exactly how to group them and
which characteristics are most important when putting them into categories. Of course
different bacteria contain different components, While some contain endospores (thick
protective structures which enable the bacteria to survive harsh conditions for decades)
or pili (Hair-like outgrowths assist the bacteria in attaching to surfaces.) others may
contain starch granules or ribosomes and enzymes. 
Bacteria come in three basic shapes, rod shaped bacteria, which are called bacilli, round
shaped bacteria, which are called cocci, and spiral shaped bacteria called spiriochetes.
Also some bacteria look like half-spirals and tiny commas, although these are really just
tiny spiriochetes, they are sometimes called vibrios. The shape of a cell does not tell
very much, not all cocci are harmful and not all spiriochetes are helpful, even though we
wish it could be that simple, it just doesn't work that way. Of course within each of
these three groups there are many variations. Some bacilli may be thin, some may be
think, some may have pointed ends, others flat ends. The possibilities are endless, as
are the different types of bacteria. Scientists have identified about 30,000 species of
bacteria but obviously there must be so many more. 
Of course there's so much more to bacteria other then how they look or what they consist
of, bacteria is what holds our world together. While many people believe that bacteria
are harmful and dangerous threats to health it is the exact opposite in some cases. When
something dies (plant or animal it doesn't matter) bacteria is what decomposes (breaks it
down into simpler material) it. What we consider rotting is just bacteria releasing
carbon and other important nutrients out of the dead organism and into the air and soil.
Aside from breaking down dead organisms they also decompose compost and sewage which
helps create methane (a natural gas used as fuel). If bacteria didn't exist the waste
would just keep accumulating at record speed and interfere with the existence of
everything living on earth. Plus decomposition returns carbon dioxide to the air which
enables plants (and the rest of the world) to survive. This natural recycling process
returns minerals to the earth and makes it fit for plants and animals. Not only this but
bacteria can actually fight the diseases they cause. Doctors are now able to take a
small, weakened dose of a disease caused by bacteria and turn it into a vaccine which is
given to people to prevent them from ever catching the illness. By giving your system a
tiny dose of the disease it learns how to fight it and becomes immune to it. Among with
vaccinations bacteria can also create antibiotics that kill the disease after it enters
your body. Antibiotics trigger the reproduction of bacteria inside of you; it cuts off
the supplies needed so it stops spreading. Unfortunately antibiotics don't always work
now in days, as the bacteria get used to them they become immune and fight back.
Antibiotics that used to work may become ineffective due to their overuse. For the time
being though, we still have plenty of useful antibiotics because of bacteria. 
Like buttermilk? Yogurt? Sour cream? If yes, you can again thank bacteria. These are just
a few foods in which go through fermentation with the help of bacteria. Bacteria usually
help in the making of dairy products and things with high fructose corn syrup. When these
foods go through fermentation the bacteria the bacteria change mild sugar into acid.
Other products are also formed through fermentation such as solvent butyl alcohol,
acetone and dextrane. Even some enzymes extracted from bacteria are used in meat
tenderizers, laundry starches, household detergents and spot removers. Without bacteria
nothing could survive, the fate of the world rests on their shoulders. Who knew that such
small creatures could have such great power. 
Bacteria reproduce by the means of binary fission. In this process the single chromosome
is doubled, the bacteria divides into two cells and each cell receives one chromosome.
You end up with two new, identical bacteria cells. Yet, this form of reproduction does
not create any type of genetic diversity (difference in genes) so to shuffle DNA bacteria
perform several processes such as conjugation, transformation and transduction. In
conjugation one bacteria attaches to another, generates a tube called a pilus, and
transfers fragments of plasmid DNA. In transformation, bacteria take up fragments of DNA
released into the soil or water from decomposing bacteria. Transduction involves the
transfer of DNA between bacteria cells by a bacteriophage (a virus that infects
bacteria.) By mixing genes in bacteria it allows them to develop new characteristics and
stronger abilities to undergo harsh conditions. 
It would be a lie to say that all bacteria are helpful, some are extremely dangerous and
cause deadly diseases. Out of the 30,000 bacteria species discovered, only a few hundred
cause diseases yet hundreds of millions have died from bacteria related sickness. The
plague was caused by a pathogens (bacteria that cause diseases) and did in fact kill
millions. Other diseases caused by bacteria include tuberculosis, tetanus, cholera and
Lyme disease. 
We haven't always known about bacteria, no one actually studied bacteria until the 1600's
when Antoni van Leeuwenhoek started to. He discovered many types of bacteria and worked
hours to make fine glass for his simple microscopes. He was considered the founder of
microbiology and set the path for other scientists like Louis Pasteur. Mr. Pasteur proved
that microbes (or any living things) did not arise from non-living matter as scientists
used to believe. Later, a German scientist named Robert Koch showed the world that
bacteria actually did cause disease. We've come far in our knowledge of bacteria from the
time, which we didn't even know it existed. Many scientists devote their lives to finding
out more about bacteria because no matter how much you know; there's always more to
learn. 
Bacteria also take part in symbiotic relationships in which they live as "partners" with
other organisms. Some bacteria form a symbiotic relationship with animals, especially
humans. While many people are unaware of it, there are bacteria throughout your body
helping you to survive. Bacteria aid in digestion in humans and other animals. They
produce nutrients and while assisting the body they get some food for themselves. Since
both benefit from this symbiosis it can also be known as a mutualism. 
That's just the basics on bacteria. It's amazing something seemingly sinple can actually
be very complex. Remember, don't shun bacteria in this world, because without them, we
wouldn't have a world.