0:01
Do you know that there are more bacteria cells in our body than in our own body? Not only that, bacteria also exist in our pets, the food and drinks we consume, and the things we use every day. Bacteria are everywhere and of course there is not only one type. Bacterial identification is very important because it functions as a basis for understanding diseases and also health.
0:28
The most basic technique used to classify bacteria based on the morphology and structure of bacterial cells that will be discussed further in this video. Hello everyone, before proceeding to the material discussion, allow me to introduce myself first. My name is Tizia Johana Limarta, a third-year student at the Faculty of Animal Medicine, Udayana University with the name 1909511006 from the A class.
0:56
This video will explain topic 2 of the Bacteriology and Micology course with the expert, Dr. Hewan I. Gusti Ketut Suarjana MP. What is a bacterium? Bacteria are unicellular microorganisms, including prokaryotic organisms, which means they do not have membranes on their intestines. Bacteria are smaller than 10 microns, so they need a microscope to be examined.
1:27
We can divide the structure of bacterial cells into two, namely the internal structure and the external structure. The internal structure consists of cytoplasm, nucleoid, ribosome, and plasma. Cytoplasm is where the metabolism happens. This colorless liquid is arranged on top of water, organic matter, mineral salt, and also enzymes. In cytoplasm, we can also find ribosomes, which are small and dense organelles that function as a place for protein synthesis.
2:00
There is also a nucleoid structure, namely nucleosome, which contains the DNA of the bacterial cell chromosomes. Many bacteria also have extra-chromosomal DNA, called plasmids. Plasmids can be replicated independently and used as a factor in genetic recursion. The bacterial external cell structure consists of the cell wall, capsule, plasma membrane, pili, fimbriae, and flagella.
2:26
The cell wall of bacteria is made up of peptidoglycan, a polysaccharide that is bound to protein. By looking at the layer of the cell wall, bacteria can be distinguished into positive gram bacteria and negative gram bacteria. Positive gram bacteria have a thick layer of peptidoglycan located on the plasma membrane, so they can withstand colorants.
2:49
while the negative gram bacteria have thinner pepidoglycan layers located between the membrane of the cell surface and the plasma membrane, so the negative gram bacteria cannot maintain the coloring agent. The bacterial cell wall functions to protect bacteria and maintain the shape of the cell, which will be discussed later in the cell bacteria morphology section.
3:09
Plasma membrane is arranged on phospholipid and protein. This structure is semi-permeable and has several functions, namely coating the cytoplasm, regulating the entry and exit of nutrients and the output of metabolism, respiration, and DNA biosynthesis. Several bacteria are coated by capsules arranged on glycoproteins. Capsules act as a layer of bacteria cells from phagocytosis and help bacteria stick to the substrate.
3:38
The capsule also shows the virulence of a bacteria and generally this structure is found in gram-negative bacteria. Pili is a type of filament that is arranged from protein peelings and grows from the bacterial cell wall. The structure is similar to flagella, but the difference is that Pili is shorter and firmer. The shorter Pili structure is called fimbriae and functions to attach bacterial cells to the substrate. Pili also functions to circulate genetic matter during conjugation.
4:09
Bacteria can also have flagella, which is arranged from flagellin protein. This structure resembles a fly and functions as a mechanism for the movement of bacterial cells. Based on the number and type of flagella, bacteria can be distinguished into five. The first is the atrial bacteria. The atrial bacteria are bacteria that do not have any flagella at all. Then there are the monotracheal bacteria, namely bacteria with one flagellum at one end of the cell.
4:35
Third, Lovotrich bacteria. This bacteria has two or more flagella at one end of the cell. Amphitrich bacteria is a bacteria that has two or more flagella at the other end of the cell. Last, Peritrich bacteria. Peritrich bacteria is a bacteria that has flagella at the entire surface of the cell. Based on its shape, bacteria can be classified as coccid, namely round, basal, bar, and spiral. There are several types of coccid bacteria cells.
5:09
Monococcus is a stem coccine bacteria cell. Diplococcus is a pair of coccine bacteria cells. Staphylococcus is a colony coccine bacteria that forms an irregular cell group and looks like a fungus. Tetracoccus is a coccine bacteria that forms a fourth group. Sarkina is a coccine bacteria that forms an eighth group and looks like a fungus. Streptococcus is a long group of bacteria that looks like a chain.
5:37
Next, the arrangement of Bacillus Bacteria. Cocobacillus is a bacterial cell that resembles a basil and a coconut. Monobacillus is a stem Bacillus Bacteria. Diplobacillus is two Bacillus Bacteria that are paired. Streptobacillus is a Bacillus Bacteria that is grouped, elongated, and resembles a chain. There are three arrangements of spiral bacterial cells, namely Spiral, Spiroceta, and Vibrio. Vibrio is a spiral bacterial cell that is slightly curved, resembling a cone.
6:08
Spirocheta is a vertebrate, so when moving, the body can stretch and shrink. Spiral bacteria are generally stiff. That's all I can say about the topic of morphology and the structure of bacteria. Thank you and see you soon.
