prokaryotes
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PROKARYOTESDomain BacteriaDomain Archaea
(Chapter 16, sections 7-17)
I. Characteristics of Prokaryotes
• A. Sizes and shapes•
coccus bacillus
spirillum
p.334
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I. Characteristics of Prokaryotes
• A. Sizes and shapes• B. No nucleus
Bacterial Genes
• Bacteria have a single chromosome– Circular molecule of DNA
• Many bacteria also have plasmids– Self-replicating circle of DNA that has a
few genes– Can be passed from one cell to
another
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pilus
bacterial flagellum
cell wallouter capsule
plasmamembrane
cytoplasm, with
ribosomes DNA, in nucleoid
Fig. 21-2, p.334
I. Characteristics of Prokaryotes
• A. Sizes and shapes• B. No nucleus• C. Most have cell walls•
pilus
bacterial flagellum
cell wallouter capsule
plasmamembrane
cytoplasm, with
ribosomes DNA, in nucleoid
Fig. 21-2, p.334
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Prokaryotic Body Plan
bacterial flagellumpilus
capsule
cell wall
plasma membrane
cytoplasm
DNA
ribosomes in cytoplasm
Fig. 21-4, p.335
Gram +
Gram -
Relates to level of peptidoglycan in cell wall
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I. Characteristics of Prokaryotes
• A. Sizes and shapes• B. No nucleus• C. Most have cell walls• D. Flagella• E. Pili
pilus
bacterial flagellum
cell wallouter capsule
plasmamembrane
cytoplasm, with
ribosomes DNA, in nucleoid
Fig. 21-2, p.334
Fig. 21-3c, p.335
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sex pilus
Fig. 21-6, p.337
ConjugationTransfer of plasmid
I. Characteristics of Prokaryotes
• A. Sizes and shapes• B. No nucleus• C. Most have cell walls • D. Flagella• E. Pili• F. Metabollic diversity
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I. Characteristics of Prokaryotes
• A. Sizes and shapes• B. No nucleus• C. Most have cell walls • D. Flagella• E. Pili• F. Metabollic diversity• G. Reproduce by fission
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II. Prokaryotic growth and reproduction
• Growth through numbers
• Processes
Fig. 21-5, p.335
Stepped Art
Fig. 21-5, p.335
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III. Classifying Prokaryotes
• Lots of gaps, very diverse group
• Biochemical analysis
III. Classifying Prokaryotes
• Lots of gaps, very diverse group
• Biochemical analysis
• Often use numerical taxonomy/strains for comparative purposes.
p.337
DOMAIN BACTERIA DOMAIN ARCHAEA
to ancestors of eukaryotic cells
biochemical and molecular origin of life
Biochemical analysis indicated first genetic divergences occurred soon after life originated.
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IV. Domain Bacteria
• A. Representative Groups
Fig. 21-7a, p.338
Bacterial Diversity
Bacteria
• Includes most familiar bacteria
• Have fatty acids in plasma membrane
• Most have cell wall; always includes peptidoglycan
• Classification based largely on metabolism
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Bacterial Diversity
• Photoautotrophic – Aerobic (Cyanobacteria)– Anaerobic (Green bacteria)
• Chemoautotrophic– Important in nitrogen cycle
• Chemoheterotrophic – Largest group
resting spore
heterocyst
Fig. 21-8a, p.339
photo-synthetic cell
Cyanobacteria
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Proteobacteria
Rhizobium sp.
Example:Monophyletic, gram -
Chlamydia
• Parasitic within animals to obtain ATP• One genus – species produce STD
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Spirochaetes
Borelia burgdorferi(Lyme disease)
Gram positives
Not a monophyletic group
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DNA
spore coat
Fig. 21-8d, p.339
capsule around cell wall
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V. Domain Archaea
V. Domain Archaea
• A. How they differ from bacteria
• How they are similar to eukaryotes
clip
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Fig. 21-11a, p.340
•Forms
Fig. 21-11b, p.340
Archaens
Methanogens
Extreme halophiles
Extreme thermophiles
Cryophiles
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Fig. 21-12c, p.341
Smallest known cell .. Nanoarchaeum equitans
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