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The word bacteria is synonymous with the term prokaryote. These are single-celled organisms that do not have a nucleus. One what to remember this is pro rhymes with no. These are believed to be the oldest forms of life on earth, dating back about 3.8 billion years. There are about 1 trillion varieties on Earth and only about .01% have been discovered.
All bacteria contain a cell membrane, the gate-keeper organelle, cytoplasm for structure and internal support, ribosomes for making protein and free-floating genetic material known as DNA and RNA.
Bacteria are organized by their shape There are 3 main shape types. the first ones listed here are the Rods. Rod shaped bacteria aka bacillus or bacilliform bacteria are one common form. There are diplobacilli that are either single rods or double rods and streptobacilli that exist as chains of rod shaped bacteria.
The second main shape are the cocci. These are single sphere shaped bacteria. Included in this are the diplococci which are pairs of cocci, streptococci that are arranged in chains of cocci and staphlococci that are cocci arranged in clusters likes grapes.
The third main bacteria shape are spirals. Vibrio are bacteria that are curved like a comma. Spirilla have a rigid spiral structure and usually have flagella. And the spirochetes which have a helical shape whose body moves and flexes like a flagellum.
Two of the most verbalized types of bacteria are the staphs and the streps. While different they do have some things in common. Both are cocci shaped and are gram positive (Will get to this in a minute). They are both anaerobic meaning they live well without oxygen present. They are spoken of a lot because of their pathogenicity meaning they are disease-causing. and both have evolved strains that have become antibiotic resistant.
These two “popular” bacteria types also have differences. They way they form for example. Strep divide on one axis to form pairs or chains, staph divide on multiple axes to form clusters. Staph can make catalase an enzyme that can break down hydrogen peroxide, strep cannot. To grow strep you need enriched media, not for staph though. And location, location, location. Staph infects the skin and strep infects the respiratory tract.
Bacteria growth occurs through binary fission which basically means that the Dna copies itself, those copies attach to the membrane and then the cell divides. this happens easy and fast. Initial growth is known as the lag phase, where the bacterial gets acclimated to its new environment. Once asjusted it reaches lag phase where it is dividing exponentially, once it reaches the carrying capacity of its environment it hits the stationary phase and if resouces become limited it hits the death phase. Of course man has found ways to inhibit or prevent bacterial growth. Changing temp is one way. high heat kills so we can autoclave, sterilize or pasteurize to kill bacteria. Life doesn’t bode well without water, so drying areas will inhibit bacteriaa growth. Gamma rays that pack a punch can penetrate bacteria and kill it. One of the ways we clean our drinking water is by filtering out bacteria. Chemicals such as chlorine and fluorine can kill bacteria. Antiseptics like mouthwash or preservatives in food can inhibit bacterial growth and of course, the ever abused antibiotic can somewhat still kill bacteria.
Bacterial testing helps us identify, trat and research bacterial strains. One way is staining bacterial. Gram staining tells us whether a bacteria has a thin or thick cell wall. Different Agars and broth are used to grow and ID certain types of bacteria. bacterial cultures are grown for food, diagnostics, and research. And sensitivity testing on bacteria can be done to see how effective an antibiotic may be on a particular strain.
So in review, bacteria are single-celled prokaryotes and have no nucleus. They come in 3 main shapes bacillus, cocci and spirals. Bacteria grow quickly via binary fission and do through different growth phases in a lifetime. There are many different ways to kill or inhibit bacterial growth as well as many ways to grow bacteria to test, identify and research.
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