Bacteria & VirusesMs. Napolitano & Mrs. HaasCP Biology

Is it Bacteria?Is it a Virus?

Is it Bacteria?Is it a Virus?

BacteriaEscherichia coli(food poisoning)

VirusInfluenza(the flu)

VirusT4 Bacteriophage

BacteriaTreponema pallidum(syphilis)

BacteriaStreptococcus pyogenes(strep throat)

3 Types of BacteriaBacilli: rod-shaped

Cocci: round

Spirilla: spiral

Examples of BacteriaBacilliSalmonellaE. coliBubonic plague

CocciStrep throatStaph infectionTSSGonorrheaPneumoniaMeningitis

SpirillaLyme diseaseRat-bite feverSyphilis

Graham StainingUsed to determine type of cell walls on

bacteriaYes, 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 capsuleRemains dormant for months or yearsEx: Anthrax virus

VirusesSmall 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

Anatomy of a Bacteriophage

RetrovirusContains RNA instead of DNA as genetic material.Ex: HIVRetro = backwards

Protein synthesis: RNA DNA

Virus Reproductive Cycle

Are viruses living?

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 & BacteriaVaccines prevent bacterial & some viral

diseasesWeakened or killed forms are injected to produce

immune response

Antibiotics kill living bacteria, but cannot kill viruses!