Chapter 19

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