Describe a time in your life when you were really sick. Do you know if you had a virus or a bacterial infection (maybe it was something else!) What were the symptoms and how was it treated? Warm-up:

The Difference in Size Bacteria can be measured in micrometers – m or Viruses are measured in nanometers – m or 10 -9

The Difference in Definition BacteriaBacteria: Prokaryotic Organisms –Pro: Primitive or “prior to” –Karyon: Nucleus or “kernel” –Single-celled organisms VirusesViruses: Submicroscopic, parasitic, acellular entity composed of a nucleic acid core surrounded by a protein coat. –Below the resolution of a microscope –Relies on a host –Does not have the properties of cellular life Prokaryo Submicroscopic parasitic acellular

Bacteria Two main “domains” 1.Archaea Cell walls lack peptidoglycan Adapted to extreme environments: Extremely hot and cold, salty, without oxygen, etc. 2.Bacteria Cell walls with peptidoglycan peptidoglycan Made up of types of peptide and sugar bonds

Bacteria: Shapes Three basic shapes: –Rod (Bacilli) Bacillus anthracis (Anthrax), Yersinia pestis (Bubonic plague) Comma-shaped (Vibrios) Vibrio cholerae –Sphere (Cocci) Streptococcus, Staphylococcus –Spiral (Spirilla) Treponema pallidum (Syphillis)

Bacterial Staining Gram-positive: Retains the crystals of violet dye in the peptidoglycan layer

Gram-negative: Will not pick up the violet dye Bacterial Staining

Bacterial Growth and Reproduction Binary Fission: Asexual division Conjugation: “Sexual” reproduction Pilus extends between bacteria Spore Formation: An endospore forms when growth conditions are unfavorable