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Viruses
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Virus “intracellular parasites”
small infectious agent that can replicate only inside the living cells of organisms
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Chicken Pox and Shingles Virus
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Virion: an entire virus particle
Consists of: DNA or RNA Protein Coat – called a capsid Sometimes a lipid envelope around the protein coat You Tube Lytic Cycle (2:17)
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Bacteriophage Virus capsid
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Sometimes glycoprotein spikes to help the virus enter and exit the host cell
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LYTIC INFECTION Animation of a Lytic Infection
McGraw Hill Life Cycle of a T2 Phage
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HIV The Human Immunodeficiency Virus (HIV)
Can lead to AIDS (acquired immunodeficiency syndrome)
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HIV INFECTION HIV infection: a retrovirus (high level)
Shows receptors and how anti-viral drugs can be effective HIV budding from a lymphocyte
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Lytic Infection
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Examples Lytic Infections
Common Cold Influenza Rabies TMV (tobacco mosaic virus)
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Lysogenic Infection
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Temperate Viruses Also called lysogenic viruses
are those that reproduce without killing their host cell.
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Common Lysogenic Virus
Herpes (genital and cold sore) Papilloma HPV (cervical cancer) Retrovirus Hepatitis B Chicken Pox
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Retroviruses Retroviruses use RNA instead of DNA as their nucleic acid core. also contain the enzyme reverse transcriptase
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Retrovirus Examples HIV Rous sarcoma (first one discovered)
Leukemia viruses
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Viroids Viroids are naked circular RNA (no protein coat) molecules that are several hundred nucleotides long. Infect plants
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Viroid Attack on Potatoes
Used to make varieties in flowers
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Prions a form of a normal protein that is not folded correctly.
Cause degenerative brain disease
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Mad Cow Disease BSE = bovine spongiform encephalitis
It's ...BSE You Tube Can cause CJD in humans
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CJD Creutzfeldt-Jakob disease (CJD) is a form of brain damage that leads to a rapid decrease of mental function and movement. You Tube The BSE Prion and Variant CJD
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Vaccines “Harmless” variants or derivatives of pathogenic microbes that stimulate the immune system to make antibodies against the pathogen.
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Edward Jenner First Vaccine (for smallpox)
Gave cowpox to his son first Lots of people were getting smallpox
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BACTERIA Prokaryotes Most of its DNA is in a single chromosome
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Bacteria Can Transfer DNA in 3 Ways
1. Transformation – uptake of foreign DNA from the surrounding environment 2. Transduction – transfer of bacterial genes by a bacteriophage 3. Conjugation – physical union of two bacterial cells as they “mate”
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Transformation
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Transduction
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Conjugation
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Bacterial Plasmids F Factor = fertility plasmid
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F Plasmid Resistance Plasmid Carry genes to destroy antibiotics
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Identifying Bacteria McGraw Hill Prokaryotic Cell Shapes
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Can you name these shapes?
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Can you name these shapes?
A Bacilli with and without flagella B Streptococci C Staphylococci D Diplococci E Spirochete F Club rod G Filamentous H Streptobacilli
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Spores dormant, tough, and non-reproductive structure produced by certain bacteria
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