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Prokaryotes:
Archaea & Bacteria
The Tree of Life
All living things classified in three domains:
BacteriaArchaeaEukarya
All living things classified in three domains:
BacteriaArchaeaEukarya
Amazing Living Things
Microbes important to all life: DecompositionOver half of Earth’s biomass
More bacterial cells than human cells in your body!
Prokaryotes
Prokaryotes have:DNA or RNA, ribosomes, cytoplasm, plasma
membraneMost prokaryotes have a cell wall, a capsule
(around the cell wall) and a flagellum Prokaryotes don’t have:
Organelles such as nucleus, chloroplasts, mitochondria.
Generalized Prokaryote
CapsuleCapsule
Cell WallCell WallPlasmaPlasmaMembraneMembrane
CytosolCytosol
Nucleoid DNANucleoid DNA
FlagellumFlagellum
Plasmid DNAPlasmid DNA
Bacteria/Archaea Habitats (name a place, and they live
there!)They are specialists
human skin, mouth, respiratory tract, large intestine, urogenital tract, etc.
salty Dead Sea extreme pH archea in deep sea vents: 90-106o C
Aerobes and anaerobes
Some Prokaryotes Thrive in Extreme Conditions
Cyanobacteria in Yellowstone Cyanobacteria in Yellowstone Hot SpringsHot Springs
Cyanobacteria in Yellowstone Cyanobacteria in Yellowstone Hot SpringsHot Springs
ArchaeaUnique lipid membranes, cell walls, and
RNAEXTREME Environments:
Swamps, hot springs, vent communities, cow stomachs
concentrated salt environmentshot, acidic environments
Bacteria
Shape:Cocci - roundBacilli - rodSpirilla - spirals
Three Common Bacterial Shapes
(a)(a)(a)(a) (b)(b)(b)(b)
(c)(c)(c)(c)
coccicoccicoccicocci
spirillusspirillusspirillusspirillus
bacillusbacillusbacillusbacillus
The Prokaryote Flagellum
BacteriumBacteriumBacteriumBacterium
FlagellaFlagellaFlagellaFlagella
Bacteria
Reproduction
Reproduction is asexual, by simple splitting (binary fission)
Daughter cells are genetic clones of the parent cell
Binary Fission
DNADNADNADNA
Benefits of Bacteria Symbiosis (mutualism)
Ruminants’ digestive tracts Nitrogen fixing in soil, nodules on certain legumes Bacteria on/in the human body: intestines and vitamin K
and B12
Biodegradation - oil Food production - cheese, yogurt, sauerkraut Decomposers
Our Relationship With Bacteria
Harmful Bacteria Some cause disease = pathogenic In humans:
Strep throatToxins - tetanus, botulismPneumonia "Flesh-eating" bacteriaPlagueTuberculosisCholera Lyme disease
ANTIBIOTICS= anti bacterial!!!
The Causes of Tooth Decay
Transmission of Bacterial Pathogens Airborne Water Food Direct (skin contact, blood, and other body
fluids) Insects and other hosts such as deer tick
(Lyme).
Germ Theory of Disease
Theory that microorganisms are the cause of disease.
1859 – Louis Pasteur Credited with the idea that human diseases
were caused by bacteria and viruses (germ theory)
Very important discovery in the field of medicine
Also created vaccinations to prevent disease
Infectious Diseases Average age of death, in first world
countries, jumped 30+ years in last century due to antibiotics enhanced hygiene and nutrition
Antibiotic-resistant infections on the rise in hospitals in the U.S.This is due to bacterial evolution in response
to widespread use of antibiotics!