1683, on September seventeenth, the most important discovery ever made was
reported to the Royal Society in London; Antonie van Leeuwenhoek had discovered
small microorganisms on human dental plaque using his homemade microscope (CBS,
2017). He had called them animalcules, but nowadays they are more commonly
known as bacteria. Bacteria had
originated from small cells when the Earth first formed about 3 billion years
ago in Earth’s very first oceans. Since then,
they have evolved into many different types, from harmful to helpful (CBS, 2017)
(Cooper, 2000) (ENI, 2018).
Cellular Structure of Bacteria
Bacteria have several different parts. Usually, a bacteria cell typically has no
nucleus as they are prokaryotes.
However, they do have deoxyribonucleic acid, more commonly known as DNA,
which is usually a rubber-band shaped molecule; the DNA usually carries the
information to make new cells and how to make a cell’s proteins. Bacteria also have ribosomes or miniscule
circular organelles made of mostly protein and other material. The ribosomes are often used to make protein
for the bacteria and are not covered by a membrane. A bacterium also has an exterior cell wall,
used to maintain the shape of the cell.
Right inside of the cell wall, a cell membrane acts as a barrier for
most of the organelles within the cell.
The cell membrane is usually made of lipids, or fats and cholesterols,
proteins, and phospholipids, or lipids that contain phosphorus. Then, within the membrane is the cytoplasm,
which is a jelly-like material that fills up most of the cell. Bacteria will also usually have a nucleoid,
which is an irregular shaped organelle made of DNA, RNA, and some protein. The nucleoid usually sits in the cytoplasm. A bacterium may also have a flagellum, which
is essentially like a tail on the outside of a bacteria which is used for
movement (BBC, 2014) (Duffy, 2004).
reproduce asexually, which means that they reproduce using only one cell. Bacteria specifically reproduce using binary
fission. Usually, binary fission will
start with one cell replicating its DNA.
Next, it will stretch into one long cell and eventually divide into two
daughter cells. The daughter cells will
both have identical DNA, which means that if one has a certain weakness,
chances are the other cell also has the same weakness. Binary fission can and will occur many times
at once, and eventually will make as much as nearly 17 million cells in a
matter of hours. Because of that, if you
have pathogenic microbes inside your body for example, you can get sick very
quickly (Microbiology Society, 2018).
DNA of Bacteria
In most cases, bacterial DNA is stored in the bacterial
chromosome, or a singular circular molecule. Along with the chromosome, bacteria also
usually have several plasmids, which also carry DNA. Despite the fact that
plasmids often have merely several genes, plasmids are very important in a
cell. Often, cells without plasmids
survive and reproduce less than a cell with plasmids. Plasmids are capable of making the host stay alive
longer in stressful situations. For
example, if the bacterium is hit by antibiotics, plasmids can provide the host
protection by resistance. Plasmids can
also help by providing genes that allow the host to digest unusual and foreign
substances or even kill other rival types of bacteria. Plasmids are very determined to stay within a
cell. Some kinds have a poison that can
kill a cell if the cell does not have the antidote regularly from the plasmid;
this allows the plasmid to metaphorically keep the host hostage (Science
Learning Hub, 2018).
Bacteria often do many interesting actions.
with Other Organisms
Bacteria have a tendency to interact with other organisms. Whether it is for positive or negative reasons,
bacteria always need a host to live off of.
For example, pathogenic bacteria can enter a human body and cause a
string of different diseases, such as tuberculosis, salmonella (food
poisoning), and one of the more well known, whooping cough (pertussis) to name
a few (BBC, 2014). Some bacteria are
predatory, which means they will cannibalize other bacteria through killing and
consuming in order to survive. Some
commonly known ones are Vampirococcus and Bdellovibrio (NCBI, 1986). There are also mutualists, which are bacteria
that provide benefits for benefits.
These kinds of bacteria are often found in the human body, but they are
definitely beneficial; they live in the intestines and helps digest the food,
and in return the bacteria will receive energy after digesting food (NECSI,
Nowadays, the discovery of bacteria has benefitted mankind in
too many ways to count. The discovery of
bacteria has saved millions of lives since humans now know what causes diseases
such as cholera or tetanus, and humans are capable of making vaccinations to
prevent these illnesses along with antibiotic medication for those who are
already ill. Not only that, but the
discovery of bacteria has also helped make our foods better; thanks to the
knowledge on bacteria humans have gathered, humans are capable of making more
complex foods requiring the use of bacteria such as bread, cheese, and even
yogurt. Humans are yet to discover more
benefits of bacteria today, and the more scientists know, the more it can be used
to make bacteria mankind’s friend, not enemy.