Cell Biology/Cell types/Bacteria
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Bacteria are prokaryotic, unicellular organisms. Bacteria are very small; so much so that 1 billion could fit on 1 square centimeter of space on the human gums, and 1 gram of digested food has 10 billion bacteria. Bacteria are the simplest living organisms. Previously they fell under the Kingdom Moneran, but now they fall into two different Kingdoms: Archaebacteria and Eubacteria. There are several differences between the two.
Bacteria also have special structures: Plasmids (a small loop of DNA separate from the nuclear region, which is used for creating genetic variety, inserting into other organisms, and by genetic engineers) and Endospores (hard coat created by some bacteria in extreme conditions--this is why canning jars must be boiled for a long time).
Bacteria Reproduction is either through binary fusion (splitting of a cell with no variety in its genes) or through several other forms that produce genetic variety: Transformation (taking DNA from environment and incorparting it into themselves), Conjugation ("sex" in which cilia hook together and the Plasmids exchange genes), and transduction (viri infect the bacteria and the bacteria infects the virus with its Plasmid to move genes throughout the population).
[edit] Archaebacteria
Archaebacteria have no peptidoglycan in their cellular walls. They also have odd lipids in their cell walls. Many are able to, and often do, live in extreme places (like early Earth), and are thus called extremophiles. There are 3 types of Archaebacteria:
- Methanogens use Carbon dioxide and Hydrogen to make Methane. They are found in sewage, cows, and swamps, and they do not take in oxygen.
- Extreme Halophiles live in extremely salty places (i.e.: the dead sea and great salt lake).
- Thermoacidophiles prefer extremely hot, acidic areas (i.e.: hot springs and volcanos).
[edit] Eubacteria
Eubacteria have peptidoglycan in their cell walls, and they have no unusual lipids. Bacteria have four shapes:
- bacilli (rod shaped)
- vibrios (curved shaped)
- coccus (round shaped)
- spirilli (spiral shaped).
Eubacteria can also have prefixes before their names: strepto, indicating chains of the shaped bacteria, and straptoy, indicating clusters of the shaped bacteria. Eubacteria are tested in laboratories for Gram stains. Gram stains will determine if antibiotics will work (Gram positive) or if they will not (Gram Negative). There are four major types of Eubacteria:
- Cyano bacteria are green bacteria that infest fertilizer polluted ponds and lakes and mass produce algae
- Spirochetes are Gram negative bacteria on which antibiotics do not work
- Gram Positive (both gram positive that are used to make yogurt, strep throat is one of these)
- Proteobacteria (E-coli)
- Anchalectbacteria (gram positive because of it)
Bacteria produce poisons that can cause sickness: serotoxins, which are given off by the Gram positive bacteria, and endotoxins, which are given off by Gram negative bacteria as they die. Some bacteria that are realy strong,and also used in wars, can help with different problems like it can stop muscle spazms and can help with migrain pains. Because of this we can evolve as one nation.
