Transcript Prokaryote Structure

Taxonomy
 The modern science of taxonomy began in the mid 18th
cent.
 founded by Carolus Linnaeus
Taxonomy: Identifying, naming and classifying
of organisms.
Systematics: Science dealing with the relationship
of organisms to one another.
Phylogeny: The evolutionary history of an organism and
its relationship to other species.
Phylogenetic tree
Cladistics
 Phylogenetic tree is constructed using traits that have
been inherited from a common ancestor.
 Organisms related by descent are called a clade.
 Derived characters:
Jaws
Lungs
Amniotic membrane
Hair
No tail
Bipedal
Phylogenetic Tree from
Cladistics
 Sequence of branching implies order that new traits evolved
 Most likely hypothesis based on existing evidence
Traditional Taxonomy
 Domain (Super kingdom)
 Kingdom
 Phylum
 Class
 Order
 Family
 Genus
 Species
Kings Play Chess On Fat Guys Stomachs
Binomial System
 Linnaeus proposed a two name Latin system for
classification.
 Genus: A group of very similar organisms related by
common descent from a recent ancestor and sharing
similar physical traits.
 Species: A specific kind of organism in a genus. A
group within a genus that share the same set of
structural traits and can successfully interbreed with
one another.
 Genus and species are italicized with genus
capitalized.
Canis familiaris
Domain: Eukaryota
Kingdom: Animalia
Phylum:Chordata
Class: Mammalia
Order: Carnivora
Family: Canidae
Genus: Canis
Species: familiaris
Common name:
Dog
Pandinus imperator
 Classifying organisms:
Linnaeus: 2 kingdom- Plantae and Animalia
Whittaker: 5 kingdom- Monera, Protista, Fungi, Plantae and Animalia
Woese: 6 kingdom- Bacteria, Archaea, Protista, Fungi, Plantae and
Animalia
Woese (1996): 3 domain- Bacteria, Archaea and Eukarya
Chapter 16
Organismal Domains
Prokaryotes
Eukaryotes
 1-5 um in size
 10-100 um in size
 10X’s more biomass
 Membrane bound nucleus
 Wider range of environments
and organelles
 DNA arranged on multiple
chromosomes
 Can’t live without prokaryotes
 Greater diversity
 Single, circular chromosome
 Best known as bacteria
 Disease causing agents are
pathogens
 Can live without the other
Prokaryotic Shape
 Cocci
 Spherical and occur in chains
or clusters
 E.g. streptococcus and
staphylococci
 Bacilli
 Rod shaped and occur
singularly, in pairs, or chains
 E.g. soil organisms
 Various shapes
 Vibrios resemble commas
 Spirilla are short, rigid
helical shapes
 Spirochetes are longer, more
flexible
Prokaryote External Structure
 Cell wall
 Bacteria can be gram (+) or gram (-)


(+) simple walls with thicker peptidoglycan (sugar polymer)
(-) more complex walls with less peptidoglycan
 Lipids and carbs too that make them more threatening, toxic,
and resistant to antibiotics
 Capsule
 Sticky polysaccharides or proteins to adhere to
substrates
 Pili
 Hairlike appendages for adhesion
Prokaryote
Structure
Prokaryotic Structure
 Motility
 Flagella

Naked protein structure w/o microtubules that moves in a propeller-like
motion
 Reproduction and adaptation
 Divide by binary fission


Speed varies from hours to minutes
Limited by nutrients, competition, predation, and waste build up
 Internal Organization
 Small genetic rings that aid in resistance called plasmids
 Smaller ribosomes
 Wide range of methods to obtain nutrients
Prokaryotic Nourishment
 Biofilms
 Surface coating colonies
of prokaryotes
 Can be 1 or more species
 E.g. dental plaque, UTI’s,
or sewer treatment
Archaea
 Live where other organisms can’t survive
 Extreme halophiles
 Salt environments
 E.g Great Salt Lake, Dead Sea, or sewater evaporating ponds
 Extreme thermophiles
 Very hot water
 E.g ocean vents, or acidic conditions
 Methanogens
 Anaerobic environments with methane as a waste product
 E.g. swamps and GI tracts of animals
Bacterial Types
 9 groups
 Proteobacteria

Gram negative
 Gram positive
 Chlamydias
 Spirochetes
 Cyanobacteria
Proteobacteria
 Alpha (α)
 Live in root nodules to fix atmospheric nitrogen
 Foreign DNA carriers into crop plant genomes
 Gamma (γ)
 Photosynthetic
 Inhabit animal intestines

E.g Salmonella, Vibrio cholerae, and Escheria coli
 Delta (δ)
 Slime secreting myxobacteria
 Can form fruiting bodies for selves when food is scarce
 Attacks other bacteria
Actinomycetes
 Gram Positive Bacteria
 Form colonies of branched chains of cells or are solitary
 Found in the soil
 Streptomycin

cultured by pharmaceutical companies,
 Bacillus anthracis
 Form endospores, cell within a cell that dehydrates and lies dormant
till more favorable conditions exist
 Staphylococcus and streptococcus
 Mycoplasmas
 Lack cell walls
 Tiniest of all known cells
Other Bacterial Phyla
 Chlamydias
 Live inside eukaryotes
 Common cause of blindness (developing countries) and
most common STD (United States)
 Spirochetes
 Spiral through environments by rotating internal filaments
 E.g Treponema pallidum (syphilis) and Borrelia burgdorferi
(Lyme disease)
 Cyanobacteria
 Oxygen-generating photosynthesis (only bacteria)
 Food for freshwater and marine ecosystems
Bacterial Poisons
 Exotoxins are proteins secreted by bacteria
 Can exist in the bacteria


Clostridium tetani produces muscle spasms (lockjaw)
Staphylococcus aureus common on skin and in nasal passages
 Produces several types causing varying problems
 Acquired from genetic transfer between species
 E. coli benign resident of intestines
 Acquires genes that produce harmful effects
 Endotoxins are components of gram (-) outer membranes
 Released when cell dies or digested by defensive cell
 Cause same general symptoms

Neisseria meningitidis (bacterial meningitis) and Salmonella (typhoid
fever)
Disease Control
 Improvements in sanitation
 Water treatment and sewer systems
 Antibiotic development
 Increase in bacterial resistance
 Education
 Importance of seeking treatment
 Prevention
 Biological weapons
Biological Weapons
 Inhalation anthrax (Bacillus anthracis)
 Manufacture endospores to disperse into air

Once in lungs they multiply and produce exotoxins
 Antibiotics kill the bacteria but can’t eradicate from body
 Pnemonic plague (Y. pestis)
 Airborne as lung tissue is coughed up
 Botulinum exotoxin (C. botulinum)
 Deadliest poison on earth
 Blocks transmission of nerve signals for muscle contraction
 Limited availability of antitoxin
Bioremediation
 Use of organisms to remove pollutants
 Prokaryotic decomposers major force in sewage treatment
 Solid sludge from filters added to anaerobe colonies

Transformed into use for fertilizer or landfill
 Liquid waste over biofilms remove organic material

Released into bodies of water
 Oil spill and mining site clean up
Protists
 Structure
 Membrane bound nucleus with chromosomes
 Other organelles characteristic of eukaryotes
 Flagella and cilia in a 9+2 microtubule arrangement
 Unicellular (most)
 Most found anywhere there’s water
 Several arose from secondary endosymbiosis
 Symbiosis is a close association between 2 or more species
 Endosymbiont is a species that lives within another species
Diplomonads
 Heterotrophic
 Possibly most ancient lineage
 No DNA or electron transport chain
 Anaerobic
 E.g Giardia intestinalis
 Parasite which derives nutrition from living hosts that
are injured by it
 Waterbourne parasite often ingested from fecal
contaminated water
Parabasalids
 Heterotrophic
 Some energy anaerobically
 E.g Trichomonas vaginalis
 Travels through reproductive tract
 Males and females can be affected, but male symptoms
less common
 Metronidazole only treatment currently
 Resistance is increasing
Euglenozoans
 Crystalline rod inside the flagella
 Can be heterotrophs, photoautotrophs, and
pathogenic parasites
 E.g Trypanosoma
 Causes sleeping sickness
 Spread by African tsetse fly
 E.g Euglena
 Common in pond water
Alveolates
 Membrane-enclosed sacs below the plasma membrane
 Stabilize cell surface or regulate and ion content
 Dinoflagellates
 Marine and fresh phytoplankton
 Red tide blooms, toxins kill fish and can affect humans
 Ciliates
 2 types of nuclei, 1 for daily activities and 1 for reproduction

E.g Paramecium or Stentor
 Apicomplexans
 Parasites of animals

E.g Plasmodium which causes malaria
Amoebozoans
 Move and feed by lobe shaped
pseudopodia, temporary
extensions of the cell
 Parasitic amoebas
 Cause dysentery
 Slime molds
 Organisms found in moist, decaying matter
 Spread under favorable conditions, form spore producing
structures under less favorable ones


Plasmodium, single multinucleated mass of cytoplasm
Cellular slime molds, solitary until food is scarce
Foraminiferans and Radiolarians
 Move and feed by thread like psuedopodia
 Forams
 Marine and fresh water organisms
 Have porous shells of CaCO3 called tests

Psudopodia extend through
 Radiolarians
 Marine
 Internal shell of silica and outer test
Stramenopiles
 Multiple ‘hairy’ flagella and a single ‘smooth’ flagellum
 Water molds
 Decompose dead plants and animals
 Can be parasitic (Ireland potato famine)
 Diatoms
 Glassy cell wall of silica
 Fresh and marine organisms
 Brown algae
 Autotrophic
 Commonly called seaweed