Chapter 21Prokaryotes & Viruses

TaxonomyDomain EukaryaKingdom AnimaliaPhylum ChordataClass MammaliaOrder CetaceaFamily DelphinidaeGenus TursiopsSpecies truncatus

Bottlenose dolphin

DomainsEubacteria (Bacteria)Archaebacteria (Archaea)Eukarya

Kingdom Protista Kingdom Fungi Kingdom PlantaeKingdom Animalia

Prokaryotes vs. EukaryotesProkaryotes—simplest, most “primitive”

bacteriaEukaryotes— “true” cells, more “advanced”

Complex organisms, multicelled

ProkaryotesNo membrane around

nucleusNo true organellesSingle chromosome

(nucleoid)May have plasmids

Cell wall (most)Reproduce by

prokaryotic fission

Bacterial ShapesCoccus (cocci)—sphericalBacillus (bacilli)—rodSprillum (spirilla)—spiral, twist

Bacterial StructuresCell wall

Peptidoglycan (polysaccharide)Maintain shapeID species

Gram-positive—thick wall Stain purple

Gram-negative—thin wall Stain pink

Bacterial StructuresGlycocalyx—capsule or slime layer

Attach to structures (teeth, intestine, rocks, etc.)

ProtectionPili—thin, hair-like proteins

Adhere to surfacesAdhere to other baceria

FlagellumMovement

MetabolismPhotoautotroph

Energy from sun (photosynthesis)Carbon from CO2

ChemoautotrophEnergy from simple compounds (iron, sulfur, etc.)Carbon from CO2

PhotoheterotrophEnergy from sunCarbon from organic compounds

Chemoheterotroph (most common kind)Energy from simple compoundsCarbon from organic compounds

Prokaryotic FissionSimilar to mitosis,

but simplerDNA duplicatesDNA molecules

move to opposite sides of cell

New cell membrane & wall form across middle

Cell divides

ConjugationTransfer section of

DNA from one cell to another

Transfers genes, characteristicsAntibiotic

resistance

Domain EubacteriaCyanobacteria

One of most primitive kindPhotoautotrophsProduce oxygen“Fix” nitrogen (convert N2 gas to nitrogen

compounds)

Domain EubacteriaProteobacteria

All gram-negativeChemoautotrophsImportant to nutrient cyclesRhizobium

Roots of legumes (peas, soybeans, etc.)

Domain EubacteriaChlamydia

Intracellular parasitesOne species causes

STDSpirochaetes

Free-living, parasites, or symbionts

Motile “springs”Borrelia burgdorferi—

Lyme disease

Domain EubacteriaGram-positives

Still being sorted outChemoheterotrophs (most)Lactobacillus—dairy foods (i.e. yogurt)Bacillus anthracis—anthrax Clostridium tetani—tetanus

Domain Archaebacteria“Extremophiles”Primitive, but resemble other bacteriaDifferent cells walls (no peptidoglycan)

Domain ArchaebacteriaThermophiles

Heat loversSulfur used to make ATPTemperatures can exceed 110o C

Domain ArchaebacteriaMethanogens

Create methane gasMarshes, Antarctica, deep oceanSymbionts (termites, cattle)Important to carbon cyclingAnaerobes

Domain ArchaebacteriaHalophiles

Salt loversEnvironments 10x salinity

of sea waterDead Sea, Great Salt

Lake

Living things must….Acquire energyMetabolizeMaintain homeostasisGrowReproduceRespondAdapt

VirusesNoncellularInfectious parasiteTwo main characteristics

Protein coat around nucleic acid (DNA or RNA)

Cannot reproduce itself

VirusesHerpesSmallpoxHepatitis BRhino virus (common cold)HIVInfluenzaRabies

Viral MultiplicationAttachmentPenetrationReplication & synthesisAssemblyRelease

Viral MultiplicationLytic Pathway—host

cell bursts (lysis) & dies, releasing viruses

Very rapid

Viral MultiplicationLysogenic

Pathway—host cell lives, viral DNA merges w/ host’s & is duplicated w/ host DNA

Latent Periodvirus in lysogenic

pathway, reproducing but not showing disease

Stress or other stimulus signals virus into lytic pathway

Herpes virus

Viral Multiplication