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TSR Wiki > Study Help > Subjects and Revision > Revision Notes > Biology > Bacteria
- True cells with a wall, membrane, cytoplasm, ribosomes and DNA.
- DNA not incorporated in chromosomes but comprising a single, circular strand.
- Bacteria may have plasmids a circle of a few genes which can move between bacteria. These may contain antibiotic resistant genes. These are often used as a vector in genetic engineering.
- Membranebounded organelles are absent.
- Cell wall of protein and polysaccharide.
- Motile if possess flagella.
- Spherical (cocci), rod shaped (bacilli) or spiral shaped (spirilla)
- Most are heterotropic obtaining energy from the oxidation of breakdown of organic matter. They are parasitic, saprobiontic or mutualistic.
- Some are chemaoautotrophic obtaining energy from the oxidation of inorganic materials.
- Some are photoautotrophic.
- Bacteria reproduce by binary fission.
- Bacteria are a source of antibiotics.
- Pathogenic bacteria are intercellular parasites and the symptoms of a disease are often caused by the toxins they produce.
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