. Chapter 10 Characterizing and Classifying Prokaryotes 10/1/11MDufilho1.
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. Chapter 10 Characteriz ing and Classifying Prokaryotes 10/1/11 MDufilho 1
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Transcript of . Chapter 10 Characterizing and Classifying Prokaryotes 10/1/11MDufilho1.
.
Chapter 10
Characterizing and Classifying
Prokaryotes
10/1/11 MDufilho 1
General Characteristics of Prokaryotic Organisms
• Prokaryotes– Most diverse group of cellular microbes
– Habitats– From Antarctic glaciers to thermal hot springs– From colons of animals to cytoplasm of other
prokaryotes– From distilled water to supersaturated brine– From disinfectant solutions to basalt rocks
– Only a few capable of colonizing humans and causing disease
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Figure 11.1 Typical prokaryotic morphologies
Coccus
Coccobacillus
Bacillus
Vibrio
Spirillum
Spirochete
Pleomorphic
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General Characteristics of Prokaryotic Organisms
• Arrangement of Prokaryotic Cells– Result from two aspects of division during
binary fission– Planes in which cells divide– Separation of daughter cells
© 2012 Pearson Education Inc.
Figure 11.6 Arrangements of cocci-overview
Figure 11.7 Arrangements of bacilli-overview
General Characteristics of Prokaryotic Organisms
• Reproduction of Prokaryotic Cells– All reproduce asexually
– Three main methods– Binary fission (most common)– Snapping division– Budding
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Figure 11.2 Binary fission
Cell replicates its DNA.
Nucleoid
Cell wallCytoplasmicmembraneReplicatedDNA
The cytoplasmicmembrane elongates,separating DNAmolecules.
Cross wall forms;membraneinvaginates.
Cross wall formscompletely.
Daughter cellsmay separate.
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Figure 11.3 Snapping division-overview
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Figure 11.4 Actinomycetes spores
Spores
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Figure 11.5 Budding
DNA is replicated
One daughter DNAmolecule is movedinto bud
Young bud
Daughter cell10/1/11 MDufilho 11
Figure 11.6 Arrangements of cocci-overview
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Figure 11.7 Arrangements of bacilli-overview
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General Characteristics of Prokaryotic Organisms
• Endospores– Produced by Gram-positive Bacillus and Clostridium
– Each vegetative cell transforms into one endospore
– Each endospore germinates to form one vegetative cell
– Defensive strategy against unfavorable conditions– Concern to food processors, health care
professionals, and governments
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Figure 11.8 Locations of endospores-overview
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Modern Prokaryotic Classification
• Currently based on genetic relatedness of rRNA sequences
• Three domains– Archaea
– Bacteria
– Eukarya
.
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Figure 11.9 Prokaryotic taxonomy
PHYLUM CHLOROFLEXI(green nonsulfur)
Thermophilicbacteria
PHYLUM DEINOCOCCUS-THERMUS
Deeply branching bacteria
PHYLUM AQUIFICAE
GRAM-NEGATIVE BACTERIA
PHYLUM PROTEOBACTERIA
Rickettsias ()Rhodospirilla ()
(purple nonsulfur)
Rhizobium ()
Nitrifying ()
Myzobacteria ()
Campylobacteria ()
Pseudomonads ()
PHYLUMCHLOROBI(green sulfur)
Neisserias ()
PHYLUMBACTEROIDETES
PHYLUM FIBROBACTERES
PHYLUM CHLAMYDIAE
PHYLUM SPIROCHAETESPHYLUMPLANCTOMYCETES
PHYLUM CYANOBACTERIA
BACTERIA
ARCHAEA
PHYLUM FUSOBACTERIAPHYLUM FIRMICUTESClostridia
Mycoplasmas
Bacilli-Lactobacilli
Arthrobacter
Streptomyces
AtopobiumCorynebacteriumMycobacteriumNocardia
PHYLUM ACTINOBACTERIA
GRAM-POSITIVE BACTERIA High G+C Gram-positive
PHYLUM KORARCHAEOTA
PHYLUM EURYARCHAEOTA
PHYLUMCRENARCHAEOTA
Thermophilicarchaea
Methanogens
Halophiles
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