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Chapter 19. Bacteria & Viruses. Identifying Prokaryotes. Shape Bacilli- rod shaped Cocci - sphere shaped Spirilla - spiral shaped Cell walls- Gram staining Eubacteria stain purple (gram +) Archaeabacteria stain red (gram -) Movement. Bacterial Diversity. Heterotrophs
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Chapter 19 Bacteria & Viruses
Identifying Prokaryotes • Shape • Bacilli- rod shaped • Cocci- sphere shaped • Spirilla- spiral shaped • Cell walls- Gram staining • Eubacteria stain purple (gram +) • Archaeabacteria stain red (gram -) • Movement
Bacterial Diversity • Heterotrophs • Chemoheterotrophs • Photoheterotrophs • Autotrophs • Photoautotrophs • Chemoautotrophs • Obligate aerobes • Obligate anaerobes • Facultative anaerobes
Bacterial Growth & Reproduction • Binary Fission • Replicates and splits • Conjugation • Exchange genetic information • Spore Formation • Encapsules DNA • Enables bacteria to survive harsh conditions
Importance of Bacteria • Decomposers • Nitrogen Fixers • Human Uses • Sewage treatment • Cleaning oil pills • Making enzymes • Digestion
What is a Virus? • Composed of DNA or RNA surrounded by a protein coat called a capsid
Viral Infection • Lytic infection • A virus enters, makes copies and bursts the host’s cell • Lysogenic infection (prophage) • A virus integrates its DNA into the hosts DNA and replicates with it
Retroviruses • Infect a cell and produce a DNA copy of their RNA in the host cell • Can cause cancer and HIV/AIDS
Diseases Caused by Bacteria and Viruses • Pathogens- disease causing agents • Bacteria cause disease by destroying and eating cells or producing toxins
Preventing Bacterial Disease • Vaccines • Stimulates the bodies immunity • Antibiotics • Compounds that block growth and reproduction of bacteria • Sterilization, disinfection and food processing
Viral Disease in Humans • Disrupt normal eqilibrium by destroying certain cells in the body • Can not be treated by antibiotics • Prevention is the only defense • Vaccination • Cleanliness
Viroids and Prions • Viroids infect plants • Single strand RNA with no capsid • Prions infect animals • Contain no DNA or RNA only protein