1. Prokaryotes and the nonliving
Archaea & Bacteria Domains
with Viruses
C2, pp24-46.

2. Prokaryotic facts Most numerous organisms on Earth
Earth’s earliest fossils (Bacteria 3.5 x 109 yrs old; Archaean x 109 yrs ago).
Lack membrane-bound organelles
rRNA analysis shows Archaea linked more to Eukaryotes than to Bacteria
Generally have cell wall, cell membrane, cytoplasm with ribosomes, DNA, & small ions/ molecules

3. Archaea vs. Bacteria Cell walls DNA Sporulation Groups
Bacteria have peptidoglycans. Archaea don’t.
DNA
Archaea have introns. Bacteria don’t.
Sporulation
Some bacteria do. Archaeans don’t.
Groups
A: Methanogens, halophiles, thermoacidophile
B: Bacilli, cocci, spirilla; gram-pos & gram-negative

4. Bacterial Cell Characteristics
Capsule: protects & aids in attachments
Cell wall: protects & gives shape
Cell membrane: control passage in/out of cells
Plasmid: carries genes in small DNA loop
Endospore: contains DNA; thick-coated
Pilus: attachment during conjugation
Flagellum: propels cells
Gram-neg outer membrane: deflect antibiotics

5. Bacteria Nutrition Autotroph Heterotroph
Photoautotroph (uses sunlight; gets C from CO2)
Chemoautotroph (gets Energy from inorganic compound; gets Carbon from CO2)
Heterotroph
Photoheterotroph (uses Light Energy but get Carbon from other organisms)
Chemoheterotroph (gets energy & C from other organisms)

6. Prokaryotic Reproduction
Single circular loop of DNA is copied
Binary fission yields 2 identical daughter cells
Exchanging DNA
Lateral gene transfer
Between different species; natural conditions
Transformation
Gets DNA from its outside environment
Conjugation
Gets DNA from other prokaryote via sex pilus
Transduction
Virus copies piece of host DNA & transfers it to others

7. Prokaryotic Habitats Obligate anaerobes = no O2 allowed
Facultative anaerobes = + O2 is OK
Obligate aerobes = O2 necessary
Psychrophilic = cold-loving (0oC – 20oC)
Mesophiles = average (20o-40oC)
Thermophiles = hot-loving (45o- 110oC)
Acidophiles = pH at or below 6.0
Most prefer neutral pH range of 6.5 – 7.5

8. Bacterial disease Disease Bacterium Anthrax Botulism Tetanus Cholera
Gonorrhea
Dental caries
Food poisoning
Lyme disease
Bacterium
Bacillus anthracis
Clostridium botulinum
Clostridium tetani
Vibrio cholerae
Neisseria gonorrhoeae
Streptococcus mutans
Salmnella typhimurium
Borrelia burgdorferi

9. Bacteria in Industry Foods Medicine Agriculture
Fermentation  buttermilk, sour cream, yogurt
Cheeses, sauerkraut, pickles, kimchi, coffee, soy
Medicine
Acetone, acetic acid, enzymes, antibiotics, insulin
Agriculture
Endotoxins as insecticides
Bioremediation = degrade petroleum

10. Viruses Nonliving Shapes Noncellular
DNA or RNA inside a protein coat + oily envelope
No organelles for homeostasis, metabolism, or reproduction
May use RNA instead of DNA for heredity
Shapes
Helical
Icosahedral
Complex

11. Viral Classification By type of nucleic acid possessed
RNA or DNA
Shape & structure
Viral strains/ serotypes
Organism they infect (host)
Avian influenza
Can jump to new species, however
Place identified
Ebola from Ebola Valley, Congo region, Africa

12. Viral Diseases Rhinovirus Influenza virus HIV-1 Common cold
Evolve extremely quickly
RNA virus hijack’s host machinery
Survive on moist surface ~ 2 wks
HIV-1
Retrovirus (injected RNA  D  host DNA)
Can lie dormant for years

13. Virus Life Cycle Attach to host plasma membrane
Be engulfed into host cell
Viral coat shed
Enters host nuclei for replication
Produces viral proteins on host’s ribosomes
Nucleic acid is housed in protein
New viruses exit cell via budding or cell lysis

14. Treating Viral Diseases
Antibiotics don’t work
Immune system fights back
with eosinophils & T-helper cells
with fever
But usually overwhelmed eventually
Drug cocktails
Disable viral reproduction
Can have serious side effects