Viruses, bacteria, and prions are all quite different, but they all share one commonality: they can all cause disease in humans. All three are also organic, in one way or another. Despite this, only bacteria are properly alive by most definitions. Bacteria are also the most complex, followed by viruses, and then finally, prions.
As mentioned in the introduction, bacteria are the most complex organizations that will be covered in this paper. Bacteria were among the first forms of life to evolve on Earth about 3.5 million years ago. This has allowed them to become one of the most diverse groups of life, from the photosynthetic cyanobacteria, to the parasitic bacteria that infect humans. Despite being so diverse, bacteria are
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The various methods of this horizontal gene transfer are: transformation, which takes place when a bacterium absorbs naked DNA from its environment, conjugation, in which two bacteria connect via conjugation pilus to exchange DNA, and transduction, which is the transfer of DNA through bacteriophages. Although bacteria can often be helpful to other organisms as they synthesize organic compounds and decompose waste, they can also cause disease. In humans, these diseases include cholera and bubonic plague. Cholera is transmitted via contaminated water supplies, physical contact without proper sanitation, and the ingestion of contaminated food. It is common in regions of high population density but poor sanitation. The typical cause of death is dehydration through extreme diarrhea since the infection typically manifests itself in the gastrointestinal tract. Plague, other hand, spreads and kills in an entirely different fashion, showcasing the diversity of bacteria. The main transmission vector for plague is via fleas carried on rodents, but it can also be spread by inhaling droplets expelled by a patient’s coughing. Once infected, the bacteria invade the lymph nodes, causing them to swell. At this point, the infection becomes systemic and the person usually dies. If the person does not die at this point, the lymph nodes may burst open and release infected pus. The plague may instead