Bacteria & Viruses Ms. Napolitano & Mrs. Haas CP Biology
Is it Bacteria?Is it a Virus? Bacteria Treponema pallidum (syphilis) Bacteria Escherichia coli (food poisoning) Virus Influenza (the flu) Bacteria Streptococcus pyogenes (strep throat) Virus T4Bacteriophage
3 Types of Bacteria Bacilli: rod-shaped Cocci: round Spirilla: spiral
Examples of Bacteria Bacilli Salmonella E. coli Bubonic plague Cocci Strep throat Staph infection TSS Gonorrhea Pneumonia Meningitis Spirilla Lyme disease Rat-bite fever Syphilis
Graham Staining • Used to determine type of cell walls on bacteria • Yes, bacteria have cell walls! • Either graham-positive or graham-negative
Bacteria can grow & reproduce quickly! • Only ~20 minutes for some species! • Binary fission – cell doubles in size & splits (mitosis) • Conjugation – genes move from 1 cell to the other • Good for genetic diversity • Spores – DNA enclosed in a capsule • Remains dormant for months or years • Ex: Anthrax virus
Viruses Small particles that carry diseases Can only reproduce by infecting living cells Very small! Usually can’t be seen with a light microscope Made of DNA or RNA surrounded by a protein coat
Types of Viruses Animal virus – infects animals Bacteriophage – infects bacteria
Retrovirus • Contains RNA instead of DNA as genetic material. • Ex: HIV • Retro = backwards • Protein synthesis: RNA DNA
Are viruses living? No!!!! They cannot reproduce on their own. They are not made of cells. They have no energy metabolism. They do not grow. They do not respond to stimuli.
Preventing/Treating Viruses & Bacteria • Vaccines prevent bacterial & some viral diseases • Weakened or killed forms are injected to produce immune response • Antibiotics kill living bacteria, but cannot kill viruses!