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Chapter 16 Bacteria and Archaea
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Bacterial biofilms cause plaque.
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Learning Outcomes Describe the primary characteristics of bacteria
Identify the features and functions of structures found in bacteria. Identify how bacteria are classified Describe the vertical and horizontal transmission of genetic material in bacteria
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Learning Outcomes Differentiate and compare archaea with bacteria.
Describe the different ways bacteria obtain energy from the environment. Describe how bacteria interact with other species in the environment.
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16.1 Prokaryotes Are a Biological Success Story
Single-celled organism that lacks a nucleus and membrane-bounded organelles 2 prokaryotic domains Bacteria Archaea Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. DOMAIN BACTERIA TEM (false color) 1 µm DOMAIN ARCHAEA SEM (false color) 1 µm Prokaryotes DOMAIN EUKARYA Animals DOMAIN BACTERIA DOMAIN ARCHAEA Fungi Plants Protista (top): © Kwangshin Kim/Photo Researchers; (middle): © Ralph Robinson/Visuals Unlimited/Getty Images Figure 16.1 Diversity of Prokaryotic Life.
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A. Microscopes Reveal Cell Structures Internal structures
16.2 Prokaryote Classification Traditionally Relies on Visible Features A. Microscopes Reveal Cell Structures Internal structures Cell membrane, DNA, cytoplasm, ribosomes Nucleoid Plasmids Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Nucleoid (chromosomal DNA) Plasmid Pilus Cytoplasm Ribosome Cell membrane Cell wall Glycocalyx Flagellum Figure 16.2 Prokaryotic Cell.
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A. Microscopes Reveal Cell Structures External structures
16.2 Prokaryote Classification Traditionally Relies on Visible Features A. Microscopes Reveal Cell Structures External structures Cell wall Peptidoglycan 3 common shapes Coccus, bacillus, spirillum Arrangements can also be important Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a. Coccus b. Bacillus c.Spirillum SEM (false color) 1.5 µm SEM (false color) 10 µm LM a: © David M. Phillips/Visuals Unlimited; b: © SciMAT/Photo Researchers; c: © Ed Reschke/Peter Arnold/Photolibrary` 100 µm Figure 16.3 Cell Shapes.
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© Jack Bostrack/Visuals Unlimited
16.2 Prokaryote Classification Traditionally Relies on Visible Features A. Microscopes Reveal Cell Structures External structures Gram stain Gram-positive Thick peptidoglycan layer Gram-negative Thinner cell walls Outer membrane Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Gram-negative cell Gram-positive cell LM 10 µm © Jack Bostrack/Visuals Unlimited Figure 16.4 Gram Stain.
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A. Microscopes Reveal Cell Structures External structures
16.2 Prokaryote Classification Traditionally Relies on Visible Features A. Microscopes Reveal Cell Structures External structures Glycocalyx Capsule or slime layer Pili Attachment or DNA transfer Flagellum Not the same as eukaryote Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Flagella Glycocalyx Glycocalyx Pili Pili a. TEM (false color) 0.5 µm b. TEM (false color) 0.5 µm c. TEM (false color) 0.5 µm a: © George Musil/Visuals Unlimited; a: © CNRI/Photo Researchers; c: © Dr. Fred Hossler/Visuals Unlimited Figure 16.5 External Structures of Prokaryotic Cells.
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© Michael Abbey/Photo Researche
16.2 Prokaryote Classification Traditionally Relies on Visible Features A. Microscopes Reveal Cell Structures Endospores Dormant, thick-walled structures Clostridium botulinum Botulism Bacillus anthracis Anthrax Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Endospore Figure 16.6 Endospores. LM 4 µm © Michael Abbey/Photo Researche
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16.2 Prokaryote Classification Traditionally Relies on Visible Features
B. Metabolic Pathways May Be Useful in Classification Autotrophs Carbon from inorganic sources Heterotrophs Carbon from organic sources Phototrophs Derive energy from sun Chemotrophs Oxidize inorganic or organic chemicals
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B. Metabolic Pathways May Be Useful in Classification Photoautotroph
16.2 Prokaryote Classification Traditionally Relies on Visible Features B. Metabolic Pathways May Be Useful in Classification Photoautotroph Plants and cynaobacteria Sunlight for energy and CO2 for carbon Chemoheterotroph Disease-causing bacteria use host as carbon and energy source
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B. Metabolic Pathways May Be Useful in Classification
16.2 Prokaryote Classification Traditionally Relies on Visible Features B. Metabolic Pathways May Be Useful in Classification Oxygen requirements Obligate aerobe Obligate anaerobe Facultative anaerobe
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16.2 Prokaryote Classification Traditionally Relies on Visible Features
C. Molecular Data Reveal Evolutionary Relationships Revolution in microbial taxonomy Used rRNA sequences Closer to taxonomy that reflects evolution
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16.3 Prokaryotes Transmit DNA Vertically and Horizontally
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Vertical gene transfer Transmit DNA from generation to generation as they reproduce Binary fission asexual Cell membrane 1 Parent cell contains one chromosome. DNA Cell wall 2 DNA replicates and attaches to cell membrane. 3 Membrane growth between the two attachment points moves the DNA molecules apart as new cell wall material is deposited. 4 The result of binary fission: two daughter cells, each identical to the original. Figure 16.7 Vertical Gene Transfer.
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16.3 Prokaryotes Transmit DNA Vertically and Horizontally
Horizontal gene transfer Transformation Naked DNA Transduction Virus mediated Conjugation Sex pilus Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a. Transformation DNA fragments Plasmid Chromosome b. Transduction Virus containing DNA from another cell c. Conjugation Donor cell Recipient cell Sex pilus through which DNA is transferred Figure 16.8 Horizontal Gene Transfer.
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16.4 Prokaryotes Include Two Domains with Enormous Diversity
A. Domain Bacteria Includes Many Familiar Groups 23 phyla Evolutionary relationships unclear Phylum Proteobacteria Exemplify overall diversity Helicobacter, E.coli, Salmonella Cyanobacteria First to produce O2 from photosynthesis Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a. TEM (false color) 0.5 µm b. LM 7 µm (left): © John Walsh/Photo Researchers; (right): © Dr Gopal Murti/Photo Researchers Figure 16.9 Two Types of Bacteria.
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16.4 Prokaryotes Include Two Domains with Enormous Diversity
B. Many, But Not All, Archaea Are “Extremophiles” Originally found in very hot, acidic, or salty environments 3 phyla Important roles in global element cycling Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. SEM (false color) 1 µm © Ralph C. Eagle, Jr./Photo Researchers; (inset): © Eye of Science/Photo Researchers Figure Extremophiles.
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16.5 Bacteria and Archaea Are Important to Human Life
A. Microbes Form Vital Links in Ecosystems Microbes play essential role in global carbon cycle Nitrogen fixation Convert atmospheric nitrogen to ammonia Rhizobium Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Nodule a. b. SEM 4 µm a: © Dr. John D. Cunningham/Visuals Unlimited; b: © Science VU/Visuals Unlimited Figure Nitrogen-Fixing Bacteria.
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16.5 Bacteria and Archaea Are Important to Human Life
B. Bacteria and Archaea Live in and on Us Normal residents are beneficial Crowd out disease-causing bacteria No archaea cause human disease May release harmful toxins May trigger immune reaction Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Scalp Eyes Nose and throat (upper respiratory system) Mouth Skin Large intestine Urinary and genital systems (lower urethra in both sexes and vagina in females) Figure A Human Habitat.
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16.5 Bacteria and Archaea Are Important to Human Life
C. Humans Put Many Prokaryotes to Work Foods- sauerkraut, vinegar, cheese Industry – vitamins, ethanol, acetone Transgenic bacteria – insulin Water and waste treatment Figure Bacteria at Work.
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16.6 Investigating Life: A Bacterial Genome Solves Two Mysteries
Staphylococcus aureus Variety of symptoms from genetic diversity Studies 37 strains Used DNA microarrays Interested in origin of MRSA Found it had multiple origins not just 1 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. MRSA Toxic shock syndrome COL MSA3410 MSA890 MSA3426 MSA817 MSA961 MSA820 MSA3400 MSA3405 MSA2120 RF122 MSA2965 MSA2348 MSA2020 MSA535 MSA551 MSA2389 MSA1601 MSA2099 MSA3412 MSA3407 M S A 2 8 8 5 MSA2335 MSA2754 MSA2345 MSA1836 MSA1827 MSA700 MSA2786 MSA3095 MSA2346 MSA1205 MSA1832 MSA537 MSA3418 MSA3402 MSA1695 Figure Staphylococcus aureus Relationships.
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16.6 Investigating Life: A Bacterial Genome Solves Two Mysteries
Origin of toxic shock syndrome epidemic of 1980 Most linked to tampon use Found S. aureus 90% of time Found multiple strains caused epidemic Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1200 Tampon absorbency lowered Total Menstrual 1000 Nonmenstrual 800 FDA requires tampon labeling Number of cases 600 400 200 1980 1982 1984 1986 1988 1990 1992 1994 1996 Year Figure Toxic Shock Syndrome Epidemic.
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