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Bacteria & Virus
Bacteria and viruses share some characteristics: - They can both reproduce rapidly and mutate. However, bacteria are cellular and prokaryotic while viruses are non-cellular and require a host cell to reproduce. - Bacteria come in many types including autotrophs that produce their own food and heterotrophs that feed on organic material. They have cell walls and circular DNA. - Viruses have either DNA or RNA inside a protein coat and some have an additional envelope. They reproduce by taking over the machinery of living host cells. While viruses cause disease, some bacteria are useful in food webs, nitrogen fixation, and producing antibiotics.
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Bacteria & Virus
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- 2. BACTERIAL CHARACTERISTICS Bacterial Characteristics Bacteria areof immense importance because of their rapid growth, reproduction, and mutation rates, as well as, their ability to exist under adverse conditions. The oldest fossils known, nearly 3.5 billion years old, are fossils of bacterialike organisms.
- 3. • Those thatare classified as autotrophs are either photosynthetic, obtaining energy from sunlight or chemosynthetic, breaking down inorganic substances for energy . • Bacteria classified as heterotrophs derive energy from breaking down complex organic compounds in the environment. • This includes saprobes, bacteria that feed on decaying material and organic wastes.
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- 5. BACTERIA • Bacteria areoften maligned as the causes of human and animal disease. However, certain bacteria, the actinomycetes, produce antibiotics such as streptomycin and nocardicin. • Bacteria live on the roots of certain plants, converting nitrogen into a usable form. • Bacteria make up the base of the food web in many environments.
- 6. Bacteria can be anaerobes oraerobes. Bacteria have circular DNA called plasmids Bacteria have cell walls. Bacteria are prokaryotic and unicellular. Bacteria can be heterotroph or autotroph About:Bacteria Bacteria can be useful as well as pernicious.
- 7. GENERAL CHARACTERISTICS OFVIRUS Viruses are infectious agents with both living and nonliving characteristics. 1. Living characteristics of viruses a. They reproduce at a fantastic rate, but only in living host cells. b. They can mutate. 2. Nonliving characteristics of viruses • They are a cellular, that is, they contain no cytoplasm or cellular organelles. • They carry out no metabolism on their own and must replicate using the host cell's metabolic machinery.
- 8. GENERAL STRUCTURE OFVIRUS
- 9. CHARACTERISTICS OF VIRUS Virion(Virus particles) size range is ~10-400 nm All virions contain a nucleocapsid which is composed of nucleic acid (DNA or RNA) and a protein coat (capsid) Some viruses consist only of a nucleocapsid, others have additional components Envelopes • virions having envelopes = Enveloped viruses • virions lacking envelopes = Naked viruses
- 10. THE ENVELOPE Many virusesthat infect humans and other animals are enveloped. Envelopes form when viral glycoproteins and oligosaccharides associate with the plasma membrane of the host cell. All envelopes have a phospholipid bilayer.
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