Microbiology is the study of microorganisms that are too small to be seen without magnification. This
microorganisms include bacteria, viruses, fungi, and protozoa. Some of these microorganisms may be
harmful because of waste products but most of the time, these are beneficial to us humans since it helps
in digestion, also in plants it is responsible for nitrogen fixation as well as in animals it helps in cellulose
digestion and it also plays a role in industries. The organisms namely, bacteria, viruses fungi are classified
according to their characteristics. Gram stain is used in bacteria to determine whether positive or negative
to categorize them. On viruses, DNA or RNA, are used whether it is single stranded or double stranded. In
fungi they're either divided into molds which is multicellular, or yeasts which are unicellular.
The hierarchy of classification consists of three domains, bacteria, archaea and eukarya. Both bacteria and
archaea are considered as prokaryotes since it is unicellular and do not have membrane bound organelles
also, both bacteria and archaea have only one single kingdom which are bacteria and archaea to be exact,
whereas eukarya are considered as eukaryotes due to the fact that it has several different parts and no cell
wall except for fungi and plants, additionally, it has four kingdoms, protists, fungi, plants, and animals.
Each organisms has two names, the first one refers to the name of the genus that indicates which genus it
belongs to and the second one refers to the species name, bacteria are categorized based on their shapes
into different classes such as cocci (round cells), bacilli or rods and spirochete (curved). Base on the video,
the example is Staphylococcus aureus so I’m gonna use it also as an example as on what I have understand.
Staphylococcus is the genus and aureus is species. Staphylo means a bunch of grapes or resemble
clusters, coccus means round cells and aureus means gold in color.
The bacteria have different structures just like cells, they have genetic material, cytoplasm and a cell
membrane. There is a cell wall present, a plasmid which is an extrachromosomal genetic material, a flagella
that is used for movement, pili which is used for attachment, glycocalyx that serves as protection from
phagocytes. Just like plasma membrane on cells, bacteria also has a part by which it selectively allow some
molecule to pass on which is the porins,it inhibits antibiotics from entering the bacteria. In addition,
mesosomes are equivalent to mitochondria in eukaryotes which is used for respiration. As mentioned earlier
bacteria can be either classified by gram staining into gram positive or gram negative, gram positive react
and retain the colour and give blue color, whereas gram negative do not retain, and are instead coloured
red or pink. The difference between the two is that in the gram positive lack an outer membrane but are
surrounded by thick layers of peptidoglycan that has a layer of two techoic and lipotechoic acids while gram
negative has thin peptidoglycan layer and have an outer lipid membrane composed of lipopolysaccharide
in addition to proteins and phospholipids. These lipopolysaccharide molecule is toxic and is classified as
an endotoxin that elicits a strong immune response causing some symptoms when the bacteria infect
people.
After watching the short video of the introduction to microbiology, it was amazing to know the different
characteristics of bacteria, viruses and fungi, it was great to learn another mnemonic which is about the
hierarchy of classification where I could use in the future, and I also got to know what is under the
different hierarchy. I like how the speaker explained in an easy way and how the artwork is being
presented was easy to understand and not confusing.
I realized that bacteria isn’t just a bacteria alone, there are different type of bacteria, it also has parts
just like cells but different in structures, I also get to differentiate what prokaryotes from eukaryotes are.
I also realized that there are also bacteria that is beneficial to us humans, living things. Lastly, I believe
that what I learned from this video would give great advantage for me in the future.