Transcript Lab 13 Lab Lecture on Prokaryotes

Chapter 10
Characterizing
and Classifying
Prokaryotes
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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
Spirillum
Coccobacillus
Spirochete
Bacillus
Pleomorphic
Vibrio
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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.
Cell wall
Cytoplasmic
membrane
Replicated
DNA
Nucleoid
The cytoplasmic
membrane elongates,
separating DNA
molecules.
Cross wall forms;
membrane
invaginates.
Cross wall forms
completely.
Daughter cells
may 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 DNA
molecule is moved
into bud
Young bud
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Daughter cell
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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)
BACTERIA
Thermophilic
bacteria
PHYLUM DEINOCOCCUS-THERMUS
Deeply branching bacteria
GRAM-NEGATIVE BACTERIA
PHYLUM PROTEOBACTERIA
Rhodospirilla ()
(purple nonsulfur)
Rickettsias ()
PHYLUM AQUIFICAE
Nitrifying ()
Rhizobium ()
Myzobacteria ()
PHYLUM
CHLOROBI
(green sulfur)
Campylobacteria ()
Pseudomonads ()
Neisserias ()
PHYLUM CYANOBACTERIA
PHYLUM KORARCHAEOTA
PHYLUM FIBROBACTERES
PHYLUM CHLAMYDIAE
PHYLUM
BACTEROIDETES
PHYLUM SPIROCHAETES
PHYLUM
PLANCTOMYCETES
ARCHAEA
PHYLUM EURYARCHAEOTA
Methanogens
PHYLUM FIRMICUTES
PHYLUM FUSOBACTERIA
PHYLUM
CRENARCHAEOTA
Clostridia
Halophiles
Mycoplasmas
Bacilli-Lactobacilli
Streptomyces
Arthrobacter
Atopobium
Corynebacterium
Mycobacterium
Nocardia
Thermophilic
archaea
PHYLUM ACTINOBACTERIA
GRAM-POSITIVE BACTERIA High G+C Gram-positive
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