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MICROBES! Bacteria, Viruses, Protists, and Fungi. Chapters 21-23 March 2011. Chapter 20 Vocabulary. 1. Virus 2. Pathogen 3. Glycoproteins 4. Lytic cycle 5. Provirus 6. Lysogenic 7. Prions 8. Viroids 9. Pili 10.Bacillus/Coccus/Spirillum 11. Capsule
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MICROBES! Bacteria, Viruses, Protists, and Fungi Chapters 21-23March 2011
Chapter 20 Vocabulary 1. Virus 2. Pathogen 3. Glycoproteins 4. Lytic cycle 5. Provirus 6. Lysogenic 7. Prions 8. Viroids 9. Pili 10.Bacillus/Coccus/Spirillum 11. Capsule 12. Antibiotics 13.Endospores 14. Conjugation 15. Aerobic/Anaerobic
1. Virus • so small they can be seen only with the aid of a powerful electron microscope. • simplest viruses contain only a few genes, whereas the most complex may have more than a hundred genes • Most viruses infect only a very specific kind of cell. viruses that infect bacteria are called bacteriophages. Latin for poison!
2. Pathogen • Disease causing agents! Bacteria viruses fungi and protists!
3. Glycoproteins Receptor molecules on the outside of the virus. Proteins and carbohydrates attached. Used for recognition on the cell membrane or cell wall.
4. Lytic cycle In a lytic infection, a virus enters a bacterial cell, makes copies of itself, and causes the cell to burst, or lyse. Bacteriophage T4 is an example of a bacteriophage that causes such an infection. • The host cell lyses, releasing hundreds of virus particles that go on to infect other cells.
5. Provirus The virus that has become part of the DNA of the host cell. also called a prophage.
6. Lysogenic In a lysogenic infection a host cell is not immediately taken over. • The viral DNA is then copied along with the host DNA without damaging the host. • Viral DNA multiplies as the host cells multiply. • In this way, each generation of daughter cells derived from the original host cell is infected. • Bacteriophage DNA that becomes embedded in the bacterial host’s DNA is called a prophage. • Influences from the environment—radiation, heat, etc—trigger the prophage to become active.
7. Prions Miss folded proteins Cause disease No nucleic acid involved! Mad Cow disease is an example • prions, short for “protein infectious particles.” Prions are misfolded proteins in the brain that cause a chain reaction of misfolding in other normal proteins they contact, eventually clogging the brain tissue and causing disease Many animals, including humans, can become infected with prions
8. Viroids Small RNA segments Cause disease in plants Possibly can infect animals
9. Pili Attachment structures Also used for reproduction
10.Bacillus • rods
10. Coccus • Round
10. Spirillum spiral bacteria often cause bad diseases!
11. Capsule Some bacteria have a slimy layer of polysaccharides and polypeptides, allowing them to attach to objects and providing protection.
12. Antibiotics • Antibiotics interfere with bacterial cell functions!
13.Endospores Outer protective covering. Makes the bacteria more pathogenic! • Bacterial endospores are highly resistant to hostile physical and chemical conditions.
14. Conjugation Transfer of genetic material from one bacteria to another. New genetic recombination's occur
15. Aerobic/Anaerobic • Aerobic: Require oxygen • Anaerobic: • Require No Oxygen!
