prokaryotes: archaea & bacteria. the tree of life all living things classified in three domains:...

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!