Uploaded byveneethmathew
PPT, PDF15,062 views

27 lecture bacteria

This document provides an overview of a lecture on bacteria and archaea. It discusses their structural and functional adaptations that allow prokaryotes to thrive in diverse environments. Key points include: - Prokaryotes have a variety of shapes and sizes, and cell surfaces like cell walls, capsules, and fimbriae that aid environmental interactions. - They reproduce rapidly through binary fission and genetic diversity arises from high mutation rates and horizontal gene transfer between cells through transformation, transduction, and conjugation. - Adaptations like motility, endospores, metabolic pathways, and rapid evolution allow prokaryotes to be highly successful and found almost everywhere on Earth.

Embed presentation

Downloaded 358 times
1 / 129
2 / 129
3 / 129
4 / 129
5 / 129
6 / 129
7 / 129
8 / 129
9 / 129
10 / 129
11 / 129
12 / 129
13 / 129
14 / 129
15 / 129
16 / 129
17 / 129
18 / 129
19 / 129
20 / 129
21 / 129
22 / 129
23 / 129
24 / 129
25 / 129
26 / 129
27 / 129
28 / 129
29 / 129
30 / 129
31 / 129
32 / 129
33 / 129
34 / 129
35 / 129
36 / 129
37 / 129
38 / 129
39 / 129
40 / 129
41 / 129
42 / 129
43 / 129
44 / 129
45 / 129
46 / 129
47 / 129
48 / 129
49 / 129
50 / 129
51 / 129
52 / 129
53 / 129
54 / 129
55 / 129
56 / 129
57 / 129
58 / 129
59 / 129
60 / 129
61 / 129
62 / 129
63 / 129
64 / 129
65 / 129
66 / 129
67 / 129
68 / 129
69 / 129
70 / 129
71 / 129
72 / 129
73 / 129
74 / 129
75 / 129
76 / 129
Most read
77 / 129
78 / 129
79 / 129
80 / 129
81 / 129
82 / 129
83 / 129
84 / 129
85 / 129
86 / 129
87 / 129
88 / 129
89 / 129
90 / 129
91 / 129
92 / 129
93 / 129
94 / 129
95 / 129
96 / 129
97 / 129
98 / 129
99 / 129
100 / 129
101 / 129
102 / 129
103 / 129
104 / 129
105 / 129
106 / 129
107 / 129
108 / 129
109 / 129
110 / 129
111 / 129
Most read
112 / 129
113 / 129
114 / 129
115 / 129
116 / 129
117 / 129
118 / 129
119 / 129
120 / 129
121 / 129
122 / 129
Most read
123 / 129
124 / 129
125 / 129
126 / 129
127 / 129
128 / 129
129 / 129
LECTURE PRESENTATIONS For CAMPBELL BIOLOGY, NINTH EDITION Jane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson © 2011 Pearson Education, Inc. Lectures by Erin Barley Kathleen Fitzpatrick Bacteria and Archaea Chapter 27
• Utah’s Great Salt Lake can reach a salt concentration of 32% • Its pink color comes from living prokaryotes Overview: Masters of Adaptation © 2011 Pearson Education, Inc.
Figure 27.1
• Prokaryotes thrive almost everywhere, including places too acidic, salty, cold, or hot for most other organisms • Most prokaryotes are microscopic, but what they lack in size they make up for in numbers • There are more in a handful of fertile soil than the number of people who have ever lived • Prokaryotes are divided into two domains: bacteria and archaea © 2011 Pearson Education, Inc. Video: Tubeworms
Concept 27.1: Structural and functional adaptations contribute to prokaryotic success • Earth’s first organisms were likely prokaryotes • Most prokaryotes are unicellular, although some species form colonies • Most prokaryotic cells are 0.5–5 µm, much smaller than the 10–100 µm of many eukaryotic cells • Prokaryotic cells have a variety of shapes • The three most common shapes are spheres (cocci), rods (bacilli), and spirals © 2011 Pearson Education, Inc.
Figure 27.2 (a) Spherical (b) Rod-shaped (c) Spiral 1µm 1µm 3µm
Figure 27.2a (a) Spherical 1µm
Figure 27.2b (b) Rod-shaped 1µm
Figure 27.2c (c) Spiral 3µm
Cell-Surface Structures • An important feature of nearly all prokaryotic cells is their cell wall, which maintains cell shape, protects the cell, and prevents it from bursting in a hypotonic environment • Eukaryote cell walls are made of cellulose or chitin • Bacterial cell walls contain peptidoglycan, a network of sugar polymers cross-linked by polypeptides © 2011 Pearson Education, Inc.
• Archaea contain polysaccharides and proteins but lack peptidoglycan • Scientists use the Gram stain to classify bacteria by cell wall composition • Gram-positive bacteria have simpler walls with a large amount of peptidoglycan • Gram-negative bacteria have less peptidoglycan and an outer membrane that can be toxic © 2011 Pearson Education, Inc.
Figure 27.3 (a) Gram-positive bacteria: peptidoglycan traps crystal violet. Gram-positive bacteria Peptido- glycan layer Cell wall Plasma membrane 10 µm Gram-negative bacteria Outer membrane Peptido- glycan layer Plasma membrane Cell wall Carbohydrate portion of lipopolysaccharide (b) Gram-negative bacteria: crystal violet is easily rinsed away, revealing red dye.
Figure 27.3a (a) Gram-positive bacteria: peptidoglycan traps crystal violet. Peptido- glycan layer Cell wall Plasma membrane
Figure 27.3b Outer membrane Peptido- glycan layer Plasma membrane Cell wall Carbohydrate portion of lipopolysaccharide (b) Gram-negative bacteria: crystal violet is easily rinsed away, revealing red dye.
Figure 27.3c Gram-positive bacteria 10 µm Gram-negative bacteria
• Many antibiotics target peptidoglycan and damage bacterial cell walls • Gram-negative bacteria are more likely to be antibiotic resistant • A polysaccharide or protein layer called a capsule covers many prokaryotes © 2011 Pearson Education, Inc.
Figure 27.4 Bacterial cell wall Bacterial capsule Tonsil cell 200 nm
• Some prokaryotes have fimbriae, which allow them to stick to their substrate or other individuals in a colony • Pili (or sex pili) are longer than fimbriae and allow prokaryotes to exchange DNA © 2011 Pearson Education, Inc.
Figure 27.5 Fimbriae 1 µm
Motility • In a heterogeneous environment, many bacteria exhibit taxis, the ability to move toward or away from a stimulus • Chemotaxis is the movement toward or away from a chemical stimulus © 2011 Pearson Education, Inc. Video: Prokaryotic Flagella (Salmonella typhimurium)
• Most motile bacteria propel themselves by flagella scattered about the surface or concentrated at one or both ends • Flagella of bacteria, archaea, and eukaryotes are composed of different proteins and likely evolved independently © 2011 Pearson Education, Inc. Video: Prokaryotic Flagella (Salmonella typhimurium)
Figure 27.6 Flagellum Hook Motor Filament Rod Peptidoglycan layer Plasma membrane Cell wall 20 nm
Figure 27.6a Hook Motor 20 nm
Evolutionary Origins of Bacteria Flagella • Bacterial flagella are composed of a motor, hook, and filament • Many of the flagella’s proteins are modified versions of proteins that perform other tasks in bacteria • Flagella likely evolved as existing proteins were added to an ancestral secretory system • This is an example of exaptation, where existing structures take on new functions through descent with modification © 2011 Pearson Education, Inc.
Internal Organization and DNA • Prokaryotic cells usually lack complex compartmentalization • Some prokaryotes do have specialized membranes that perform metabolic functions • These are usually infoldings of the plasma membrane © 2011 Pearson Education, Inc.
Figure 27.7 (a) Aerobic prokaryote (b) Photosynthetic prokaryote Respiratory membrane Thylakoid membranes 0.2 µm 1 µm
Figure 27.7a (a) Aerobic prokaryote Respiratory membrane 0.2 µm
Figure 27.7b (b) Photosynthetic prokaryote Thylakoid membranes 1 µm
• The prokaryotic genome has less DNA than the eukaryotic genome • Most of the genome consists of a circular chromosome • The chromosome is not surrounded by a membrane; it is located in the nucleoid region • Some species of bacteria also have smaller rings of DNA called plasmids © 2011 Pearson Education, Inc.
Figure 27.8 Chromosome Plasmids 1 µm
• There are some differences between prokaryotes and eukaryotes in DNA replication, transcription, and translation • These allow people to use some antibiotics to inhibit bacterial growth without harming themselves © 2011 Pearson Education, Inc.
Reproduction and Adaptation • Prokaryotes reproduce quickly by binary fission and can divide every 1–3 hours • Key features of prokaryotic reproduction: – They are small – They reproduce by binary fission – They have short generation times © 2011 Pearson Education, Inc.
• Many prokaryotes form metabolically inactive endospores, which can remain viable in harsh conditions for centuries © 2011 Pearson Education, Inc.
Figure 27.9 Coat Endospore 0.3 µm
• Their short generation time allows prokaryotes to evolve quickly – For example, adaptive evolution in a bacterial colony was documented in a lab over 8 years • Prokaryotes are not “primitive” but are highly evolved © 2011 Pearson Education, Inc.
Figure 27.10 Daily serial transfer 0.1 mL (population sample) Old tube (discarded after transfer) New tube (9.9 mL growth medium) EXPERIMENT RESULTS 1.8 Populationgrowthrate (relativetoancestralpopulation) 1.6 1.4 1.2 1.0 0 5,000 10,000 15,000 Generation 20,000
Figure 27.10a Daily serial transfer 0.1 mL (population sample) Old tube (discarded after transfer) New tube (9.9 mL growth medium) EXPERIMENT
Figure 27.10b RESULTS 1.8 Populationgrowthrate (relativetoancestralpopulation) 1.6 1.4 1.2 1.0 0 5,000 10,000 15,000 Generation 20,000
• Prokaryotes have considerable genetic variation • Three factors contribute to this genetic diversity: – Rapid reproduction – Mutation – Genetic recombination Concept 27.2: Rapid reproduction, mutation, and genetic recombination promote genetic diversity in prokaryotes © 2011 Pearson Education, Inc.
Rapid Reproduction and Mutation • Prokaryotes reproduce by binary fission, and offspring cells are generally identical • Mutation rates during binary fission are low, but because of rapid reproduction, mutations can accumulate rapidly in a population • High diversity from mutations allows for rapid evolution © 2011 Pearson Education, Inc.
Genetic Recombination • Genetic recombination, the combining of DNA from two sources, contributes to diversity • Prokaryotic DNA from different individuals can be brought together by transformation, transduction, and conjugation • Movement of genes among individuals from different species is called horizontal gene transfer © 2011 Pearson Education, Inc.
Transformation and Transduction • A prokaryotic cell can take up and incorporate foreign DNA from the surrounding environment in a process called transformation • Transduction is the movement of genes between bacteria by bacteriophages (viruses that infect bacteria) © 2011 Pearson Education, Inc.
Figure 27.11-1 Donor cell A+ B+ B+ A+ Phage
Figure 27.11-2 A+ Donor cell A+ B+ B+ A+ Phage
Figure 27.11-3 Recipient cell Recombination A+ A+ A− B− Donor cell A+ B+ B+ A+ Phage
Figure 27.11-4 Recombinant cell Recipient cell Recombination A+ A+ A− B− B−A+ Donor cell A+ B+ B+ A+ Phage
Conjugation and Plasmids • Conjugation is the process where genetic material is transferred between prokaryotic cells • In bacteria, the DNA transfer is one way • A donor cell attaches to a recipient by a pilus, pulls it closer, and transfers DNA • A piece of DNA called the F factor is required for the production of pili © 2011 Pearson Education, Inc.
Figure 27.12 Sex pilus 1 µm
The F Factor as a Plasmid • Cells containing the F plasmid function as DNA donors during conjugation • Cells without the F factor function as DNA recipients during conjugation • The F factor is transferable during conjugation © 2011 Pearson Education, Inc.
Figure 27.13 F plasmid Bacterial chromosome F+ cell (donor) F− cell (recipient) Mating bridge Bacterial chromosome (a) Conjugation and transfer of an F plasmid Hfr cell (donor) F− cell (recipient) (b) Conjugation and transfer of part of an Hfr bacterial chromosome F factor A+ A− A+ A− A+ A+ A− F+ cell F+ cell A+A− Recombinant F− bacterium A+
Figure 27.13a-1 F plasmid Bacterial chromosome F+ cell (donor) F− cell (recipient) Mating bridge Bacterial chromosome (a) Conjugation and transfer of an F plasmid
Figure 27.13a-2 F plasmid Bacterial chromosome F+ cell (donor) F− cell (recipient) Mating bridge Bacterial chromosome (a) Conjugation and transfer of an F plasmid
Figure 27.13a-3 F plasmid Bacterial chromosome F+ cell (donor) F− cell (recipient) Mating bridge Bacterial chromosome (a) Conjugation and transfer of an F plasmid F+ cell F+ cell
The F Factor in the Chromosome • A cell with the F factor built into its chromosomes functions as a donor during conjugation • The recipient becomes a recombinant bacterium, with DNA from two different cells © 2011 Pearson Education, Inc.
Figure 27.13b-1 Hfr cell (donor) F− cell (recipient) (b) Conjugation and transfer of part of an Hfr bacterial chromosome F factor A− A+ A+ A− A+
Figure 27.13b-2 Hfr cell (donor) F− cell (recipient) (b) Conjugation and transfer of part of an Hfr bacterial chromosome F factor A+ A+ A− A− A+ A+ A− A+
Figure 27.13b-3 Hfr cell (donor) F− cell (recipient) (b) Conjugation and transfer of part of an Hfr bacterial chromosome F factor A+ A− Recombinant F− bacterium A+ A+ A− A− A+ A+ A− A+
R Plasmids and Antibiotic Resistance • R plasmids carry genes for antibiotic resistance • Antibiotics kill sensitive bacteria, but not bacteria with specific R plasmids • Through natural selection, the fraction of bacteria with genes for resistance increases in a population exposed to antibiotics • Antibiotic-resistant strains of bacteria are becoming more common © 2011 Pearson Education, Inc.
Concept 27.3: Diverse nutritional and metabolic adaptations have evolved in prokaryotes • Prokaryotes can be categorized by how they obtain energy and carbon – Phototrophs obtain energy from light – Chemotrophs obtain energy from chemicals – Autotrophs require CO2 as a carbon source – Heterotrophs require an organic nutrient to make organic compounds © 2011 Pearson Education, Inc.
• Energy and carbon sources are combined to give four major modes of nutrition: – Photoautotrophy – Chemoautotrophy – Photoheterotrophy – Chemoheterotrophy © 2011 Pearson Education, Inc.
Table 27.1
The Role of Oxygen in Metabolism • Prokaryotic metabolism varies with respect to O2 – Obligate aerobes require O2 for cellular respiration – Obligate anaerobes are poisoned by O2 and use fermentation or anaerobic respiration – Facultative anaerobes can survive with or without O2 © 2011 Pearson Education, Inc.
Nitrogen Metabolism • Nitrogen is essential for the production of amino acids and nucleic acids • Prokaryotes can metabolize nitrogen in a variety of ways • In nitrogen fixation, some prokaryotes convert atmospheric nitrogen (N2) to ammonia (NH3) © 2011 Pearson Education, Inc.
Metabolic Cooperation • Cooperation between prokaryotes allows them to use environmental resources they could not use as individual cells • In the cyanobacterium Anabaena, photosynthetic cells and nitrogen-fixing cells called heterocysts (or heterocytes) exchange metabolic products © 2011 Pearson Education, Inc. Video: Cyanobacteria (Oscillatoria)
Figure 27.14 Photosynthetic cells Heterocyst 20 µm
• In some prokaryotic species, metabolic cooperation occurs in surface-coating colonies called biofilms © 2011 Pearson Education, Inc.
Concept 27.4: Molecular systematics is illuminating prokaryotic phylogeny • Until the late 20th century, systematists based prokaryotic taxonomy on phenotypic criteria • Applying molecular systematics to the investigation of prokaryotic phylogeny has produced dramatic results © 2011 Pearson Education, Inc.
Lessons from Molecular Systematics • Molecular systematics led to the splitting of prokaryotes into bacteria and archaea • Molecular systematists continue to work on the phylogeny of prokaryotes © 2011 Pearson Education, Inc.
Eukaryotes Korarchaeotes Euryarchaeotes Crenarchaeotes Nanoarchaeotes Proteobacteria Chlamydias Spirochetes Cyanobacteria Gram-positive bacteria DomainBacteriaDomainArchaea Domain Eukarya UNIVERSAL ANCESTOR Figure 27.15
• The use of polymerase chain reaction (PCR) has allowed for more rapid sequencing of prokaryote genomes • A handful of soil may contain 10,000 prokaryotic species • Horizontal gene transfer between prokaryotes obscures the root of the tree of life © 2011 Pearson Education, Inc.
Archaea • Archaea share certain traits with bacteria and other traits with eukaryotes © 2011 Pearson Education, Inc.
Figure 27.UN01 Eukarya Archaea Bacteria
Table 27.2
• Some archaea live in extreme environments and are called extremophiles • Extreme halophiles live in highly saline environments • Extreme thermophiles thrive in very hot environments © 2011 Pearson Education, Inc.
Figure 27.16
• Methanogens live in swamps and marshes and produce methane as a waste product • Methanogens are strict anaerobes and are poisoned by O2 • In recent years, genetic prospecting has revealed many new groups of archaea • Some of these may offer clues to the early evolution of life on Earth © 2011 Pearson Education, Inc.
Bacteria • Bacteria include the vast majority of prokaryotes of which most people are aware • Diverse nutritional types are scattered among the major groups of bacteria © 2011 Pearson Education, Inc.
Figure 27.UN02 Eukarya Archaea Bacteria
Proteobacteria • These gram-negative bacteria include photoautotrophs, chemoautotrophs, and heterotrophs • Some are anaerobic, and others aerobic © 2011 Pearson Education, Inc.
Figure 27.17-a Alpha Beta Gamma Delta Proteo- bacteria Epsilon Subgroup: Alpha Proteobacteria Rhizobium (arrows) inside a root cell of a legume (TEM) 2.5µm Subgroup: Delta ProteobacteriaSubgroup: Gamma Proteobacteria Subgroup: Epsilon Proteobacteria Nitrosomonas (colorized TEM) 1µm Subgroup: Beta Proteobacteria 2µm 300µm Helicobacter pylori (colorized TEM)Fruiting bodies of Chondromyces crocatus, a myxobacterium (SEM) 200µm Thiomargarita namibiensis containing sulfur wastes (LM)
Figure 27.17a Alpha Beta Gamma Delta Proteobacteria Epsilon
Subgroup: Alpha Proteobacteria • Many species are closely associated with eukaryotic hosts • Scientists hypothesize that mitochondria evolved from aerobic alpha proteobacteria through endosymbiosis © 2011 Pearson Education, Inc.
• Example: Rhizobium, which forms root nodules in legumes and fixes atmospheric N2 • Example: Agrobacterium, which produces tumors in plants and is used in genetic engineering © 2011 Pearson Education, Inc.
Figure 27.17b Subgroup: Alpha Proteobacteria Rhizobium (arrows) inside a root cell of a legume (TEM) 2.5µm
Subgroup: Beta Proteobacteria • Example: the soil bacterium Nitrosomonas, which converts NH4 + to NO2 – © 2011 Pearson Education, Inc.
Figure 27.17c Nitrosomonas (colorized TEM) 1µm Subgroup: Beta Proteobacteria
Subgroup: Gamma Proteobacteria • Examples include sulfur bacteria such as Chromatium and pathogens such as Legionella, Salmonella, and Vibrio cholerae • Escherichia coli resides in the intestines of many mammals and is not normally pathogenic © 2011 Pearson Education, Inc.
Figure 27.17d Subgroup: Gamma Proteobacteria 200µm Thiomargarita namibiensis containing sulfur wastes (LM)
Subgroup: Delta Proteobacteria • Example: the slime-secreting myxobacteria © 2011 Pearson Education, Inc.
Figure 27.17e Subgroup: Delta Proteobacteria 300µm Fruiting bodies of Chondromyces crocatus, a myxobacterium (SEM)
Subgroup: Epsilon Proteobacteria • This group contains many pathogens including Campylobacter, which causes blood poisoning, and Helicobacter pylori, which causes stomach ulcers © 2011 Pearson Education, Inc.
Figure 27.17f Subgroup: Epsilon Proteobacteria 2µm Helicobacter pylori (colorized TEM)
Figure 27.17-b Chlamydias 5µm Spirochetes 2.5µm Leptospira, a spirochete (colorized TEM) Gram-Positive Bacteria 2µm 5µm Hundreds of mycoplasmas covering a human fibroblast cell (colorized SEM) Streptomyces, the source of many antibiotics (SEM) 40µm Oscillatoria, a filamentous cyanobacterium Cyanobacteria Chlamydia (arrows) inside an animal cell (colorized TEM)
Chlamydias • These bacteria are parasites that live within animal cells • Chlamydia trachomatis causes blindness and nongonococcal urethritis by sexual transmission © 2011 Pearson Education, Inc.
Figure 27.17g Chlamydias 2.5µm Chlamydia (arrows) inside an animal cell (colorized TEM)
Spirochetes • These bacteria are helical heterotrophs • Some are parasites, including Treponema pallidum, which causes syphilis, and Borrelia burgdorferi, which causes Lyme disease © 2011 Pearson Education, Inc.
Figure 27.17h 5µm Spirochetes Leptospira, a spirochete (colorized TEM)
Cyanobacteria • These are photoautotrophs that generate O2 • Plant chloroplasts likely evolved from cyanobacteria by the process of endosymbiosis © 2011 Pearson Education, Inc.
Figure 27.17i 40µm Oscillatoria, a filamentous cyanobacterium Cyanobacteria
Gram-Positive Bacteria • Gram-positive bacteria include – Actinomycetes, which decompose soil – Bacillus anthracis, the cause of anthrax – Clostridium botulinum, the cause of botulism – Some Staphylococcus and Streptococcus, which can be pathogenic – Mycoplasms, the smallest known cells © 2011 Pearson Education, Inc.
Figure 27.17j Gram-Positive Bacteria 5µm Streptomyces, the source of many antibiotics (SEM)
Figure 27.17k Gram-Positive Bacteria 2µm Hundreds of mycoplasmas covering a human fibroblast cell (colorized SEM)
Concept 27.5: Prokaryotes play crucial roles in the biosphere • Prokaryotes are so important that if they were to disappear the prospects for any other life surviving would be dim © 2011 Pearson Education, Inc.
Chemical Recycling • Prokaryotes play a major role in the recycling of chemical elements between the living and nonliving components of ecosystems • Chemoheterotrophic prokaryotes function as decomposers, breaking down dead organisms and waste products • Prokaryotes can sometimes increase the availability of nitrogen, phosphorus, and potassium for plant growth © 2011 Pearson Education, Inc.
Figure 27.18 Seedlings grow- ing in the lab Strain 3Strain 2 0 No bacteria Soil treatment 0.2 0.4 0.6 0.8 1.0 UptakeofKbyplants(mg) Strain 1
Figure 27.18a Seedlings growing in the lab
• Prokaryotes can also “immobilize” or decrease the availability of nutrients © 2011 Pearson Education, Inc.
Ecological Interactions • Symbiosis is an ecological relationship in which two species live in close contact: a larger host and smaller symbiont • Prokaryotes often form symbiotic relationships with larger organisms © 2011 Pearson Education, Inc.
• In mutualism, both symbiotic organisms benefit • In commensalism, one organism benefits while neither harming nor helping the other in any significant way • In parasitism, an organism called a parasite harms but does not kill its host • Parasites that cause disease are called pathogens © 2011 Pearson Education, Inc.
Figure 27.19
• The ecological communities of hydrothermal vents depend on chemoautotropic bacteria for energy © 2011 Pearson Education, Inc.
Concept 27.6: Prokaryotes have both beneficial and harmful impacts on humans • Some prokaryotes are human pathogens, but others have positive interactions with humans © 2011 Pearson Education, Inc.
Mutualistic Bacteria • Human intestines are home to about 500–1,000 species of bacteria • Many of these are mutalists and break down food that is undigested by our intestines © 2011 Pearson Education, Inc.
Pathogenic Bacteria • Prokaryotes cause about half of all human diseases – For example, Lyme disease is caused by a bacterium and carried by ticks © 2011 Pearson Education, Inc.
Figure 27.20 5 µm
Figure 27.20a
Figure 27.20b 5 µm
Figure 27.20c
• Pathogenic prokaryotes typically cause disease by releasing exotoxins or endotoxins • Exotoxins are secreted and cause disease even if the prokaryotes that produce them are not present • Endotoxins are released only when bacteria die and their cell walls break down © 2011 Pearson Education, Inc.
• Horizontal gene transfer can spread genes associated with virulence • Some pathogenic bacteria are potential weapons of bioterrorism © 2011 Pearson Education, Inc.
Prokaryotes in Research and Technology • Experiments using prokaryotes have led to important advances in DNA technology – For example, E. coli is used in gene cloning – For example, Agrobacterium tumefaciens is used to produce transgenic plants • Bacteria can now be used to make natural plastics © 2011 Pearson Education, Inc.
• Prokaryotes are the principal agents in bioremediation, the use of organisms to remove pollutants from the environment • Bacteria can be engineered to produce vitamins, antibiotics, and hormones • Bacteria are also being engineered to produce ethanol from waste biomass © 2011 Pearson Education, Inc.
Figure 27.21 (a) (b) (c)
Figure 27.21a (a)
Figure 27.21b (b)
Figure 27.21c (c)
Figure 27.UN03 Fimbriae Cell wall Circular chromosome Sex pilus Flagella Internal organization Capsule
Figure 27.UN04
Figure 27.UN05

More Related Content

PPT
Ch 13: Meiosis and Sexual Life Cycles
byveneethmathew
 
PPT
25 lecture history_of_life
byveneethmathew
 
PPT
24 lecture origin_of_species
byveneethmathew
 
PPT
Ch. 38: Angiosperm Reproduction and Biotechnology
byAndreDominic1
 
PPT
19 lecture viruses
byveneethmathew
 
PPT
28_Lecture_Presentation.ppt
byibrahimkarem
 
PPT
22 lecture descent_with_modification
byveneethmathew
 
PPT
Biology "B" / Ch42
byNoor Huda
 
Ch 13: Meiosis and Sexual Life Cycles
byveneethmathew
 
25 lecture history_of_life
byveneethmathew
 
24 lecture origin_of_species
byveneethmathew
 
Ch. 38: Angiosperm Reproduction and Biotechnology
byAndreDominic1
 
19 lecture viruses
byveneethmathew
 
28_Lecture_Presentation.ppt
byibrahimkarem
 
22 lecture descent_with_modification
byveneethmathew
 
Biology "B" / Ch42
byNoor Huda
 

What's hot

PPT
19 - Viruses
bykindarspirit
 
PPT
23 lecture evolution_populations
byveneethmathew
 
PPT
20 lecture biotech
byveneethmathew
 
PPT
13 meiosis and sexual life cycles
bykindarspirit
 
PPT
16 the molecular basis of inheritance
bykindarspirit
 
PPT
21 genomes and their evolution
bykindarspirit
 
PPT
Ch 14: Mendel and the Gene Idea
byveneethmathew
 
PPT
18 Regulation of Gene Expression
bykindarspirit
 
PPT
26 lecture phylogeny
byveneethmathew
 
PPT
Ch 8: Introduction to Metabolism
byveneethmathew
 
PPT
Ch 15: The Chromosomal Basis of Inheritance
byveneethmathew
 
PPT
17 - From Gene to Protein
bykindarspirit
 
PPT
23 the evolution of populations
bykindarspirit
 
PPT
Ch 6: A Tour of the Cell
byveneethmathew
 
PPT
Ch 11: Cell Communication
byveneethmathew
 
PPT
Ch 10: Photosynthesis
byveneethmathew
 
PPT
Ch 12: Cell Cycle
byveneethmathew
 
PPT
22 descent with modification a darwinian view
bykindarspirit
 
PPT
Ch 17: From Gene to Protein
byveneethmathew
 
PPT
Ch 16: The Molecular Basis of Inheritance
byveneethmathew
 
19 - Viruses
bykindarspirit
 
23 lecture evolution_populations
byveneethmathew
 
20 lecture biotech
byveneethmathew
 
13 meiosis and sexual life cycles
bykindarspirit
 
16 the molecular basis of inheritance
bykindarspirit
 
21 genomes and their evolution
bykindarspirit
 
Ch 14: Mendel and the Gene Idea
byveneethmathew
 
18 Regulation of Gene Expression
bykindarspirit
 
26 lecture phylogeny
byveneethmathew
 
Ch 8: Introduction to Metabolism
byveneethmathew
 
Ch 15: The Chromosomal Basis of Inheritance
byveneethmathew
 
17 - From Gene to Protein
bykindarspirit
 
23 the evolution of populations
bykindarspirit
 
Ch 6: A Tour of the Cell
byveneethmathew
 
Ch 11: Cell Communication
byveneethmathew
 
Ch 10: Photosynthesis
byveneethmathew
 
Ch 12: Cell Cycle
byveneethmathew
 
22 descent with modification a darwinian view
bykindarspirit
 
Ch 17: From Gene to Protein
byveneethmathew
 
Ch 16: The Molecular Basis of Inheritance
byveneethmathew
 

Similar to 27 lecture bacteria

PPT
27 bacteria ppt mission college
by1slid
 
PPT
Ap27 prokaryotes
byktanaka2
 
PPT
27 prokaryotes7th
byktanaka2
 
PPT
PROKARYOTES unit prepared for douynloading.ppt
byjaffarkl12
 
PPT
27_PROKARYOTESsnnanakmakakakkaoakaama_ppt.ppt
bykusoco3
 
PPT
27 prokaryotes text
byAndrew McCaskill
 
PPT
Chapter 27
byguest970cb3
 
PPTX
Presentation 3
byMona Othman Albureikan / King Abdulaziz University
 
PPT
Chapter 4 functional anatomy of prok and euk partial
byBilalHoushaymi
 
PDF
morphphysioofbacteriadr-180131090251.pdf
bydawitg2
 
PPTX
Ch 04_lecture_presentation
bykevperrino
 
PDF
Bacteriology Anatomy of Prokaryotic
byMona Othman Albureikan / King Abdulaziz University
 
PPTX
Functional Anatom of Prokarytic and Eukaryotic2026.pptx
byalhagjenin1
 
PPTX
Functional Anatom of Prokarytic and Eukaryotic2026.pptx
byalhagjenin1
 
PPTX
Functional Anatom of Prokarytic and Eukaryotic2026.pptx
byalhagjenin1
 
PDF
3-Prokaryotic Eukaryotic Cells. BioSel PBIO
byEchySitokdana
 
PPT
Bacteria and archea f12 (2)
byrhkelso
 
PPTX
Lecture 2
byalyssa1014
 
PDF
L4-BIOLOGY I-BIOL 231-prokatotes-Bacteria.pdf
byDodoElbadan1
 
PPT
Kingdom Monera
byNattapong Boonpong
 
27 bacteria ppt mission college
by1slid
 
Ap27 prokaryotes
byktanaka2
 
27 prokaryotes7th
byktanaka2
 
PROKARYOTES unit prepared for douynloading.ppt
byjaffarkl12
 
27_PROKARYOTESsnnanakmakakakkaoakaama_ppt.ppt
bykusoco3
 
27 prokaryotes text
byAndrew McCaskill
 
Chapter 27
byguest970cb3
 
Presentation 3
byMona Othman Albureikan / King Abdulaziz University
 
Chapter 4 functional anatomy of prok and euk partial
byBilalHoushaymi
 
morphphysioofbacteriadr-180131090251.pdf
bydawitg2
 
Ch 04_lecture_presentation
bykevperrino
 
Bacteriology Anatomy of Prokaryotic
byMona Othman Albureikan / King Abdulaziz University
 
Functional Anatom of Prokarytic and Eukaryotic2026.pptx
byalhagjenin1
 
Functional Anatom of Prokarytic and Eukaryotic2026.pptx
byalhagjenin1
 
Functional Anatom of Prokarytic and Eukaryotic2026.pptx
byalhagjenin1
 
3-Prokaryotic Eukaryotic Cells. BioSel PBIO
byEchySitokdana
 
Bacteria and archea f12 (2)
byrhkelso
 
Lecture 2
byalyssa1014
 
L4-BIOLOGY I-BIOL 231-prokatotes-Bacteria.pdf
byDodoElbadan1
 
Kingdom Monera
byNattapong Boonpong
 

More from veneethmathew

PPT
21 lecture genome_and_evolution
byveneethmathew
 
PPT
Ch 7: Membrane Structure and Function
byveneethmathew
 
PPT
Ch 5: The Structure and Function of Large Biological Molecules
byveneethmathew
 
PPT
Ch 4: Carbon and Diversity
byveneethmathew
 
PPT
Ch 3: Water and Life
byveneethmathew
 
PPT
Ch 2: The Chemical Context of Life
byveneethmathew
 
PPT
Ch 1: Themes in the Study of Life
byveneethmathew
 
21 lecture genome_and_evolution
byveneethmathew
 
Ch 7: Membrane Structure and Function
byveneethmathew
 
Ch 5: The Structure and Function of Large Biological Molecules
byveneethmathew
 
Ch 4: Carbon and Diversity
byveneethmathew
 
Ch 3: Water and Life
byveneethmathew
 
Ch 2: The Chemical Context of Life
byveneethmathew
 
Ch 1: Themes in the Study of Life
byveneethmathew
 

27 lecture bacteria

  • 1.
    LECTURE PRESENTATIONS For CAMPBELLBIOLOGY, NINTH EDITION Jane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson © 2011 Pearson Education, Inc. Lectures by Erin Barley Kathleen Fitzpatrick Bacteria and Archaea Chapter 27
  • 2.
    • Utah’s GreatSalt Lake can reach a salt concentration of 32% • Its pink color comes from living prokaryotes Overview: Masters of Adaptation © 2011 Pearson Education, Inc.
  • 3.
  • 4.
    • Prokaryotes thrivealmost everywhere, including places too acidic, salty, cold, or hot for most other organisms • Most prokaryotes are microscopic, but what they lack in size they make up for in numbers • There are more in a handful of fertile soil than the number of people who have ever lived • Prokaryotes are divided into two domains: bacteria and archaea © 2011 Pearson Education, Inc. Video: Tubeworms
  • 5.
    Concept 27.1: Structuraland functional adaptations contribute to prokaryotic success • Earth’s first organisms were likely prokaryotes • Most prokaryotes are unicellular, although some species form colonies • Most prokaryotic cells are 0.5–5 µm, much smaller than the 10–100 µm of many eukaryotic cells • Prokaryotic cells have a variety of shapes • The three most common shapes are spheres (cocci), rods (bacilli), and spirals © 2011 Pearson Education, Inc.
  • 6.
    Figure 27.2 (a) Spherical(b) Rod-shaped (c) Spiral 1µm 1µm 3µm
  • 7.
  • 8.
  • 9.
  • 10.
    Cell-Surface Structures • Animportant feature of nearly all prokaryotic cells is their cell wall, which maintains cell shape, protects the cell, and prevents it from bursting in a hypotonic environment • Eukaryote cell walls are made of cellulose or chitin • Bacterial cell walls contain peptidoglycan, a network of sugar polymers cross-linked by polypeptides © 2011 Pearson Education, Inc.
  • 11.
    • Archaea containpolysaccharides and proteins but lack peptidoglycan • Scientists use the Gram stain to classify bacteria by cell wall composition • Gram-positive bacteria have simpler walls with a large amount of peptidoglycan • Gram-negative bacteria have less peptidoglycan and an outer membrane that can be toxic © 2011 Pearson Education, Inc.
  • 12.
    Figure 27.3 (a) Gram-positivebacteria: peptidoglycan traps crystal violet. Gram-positive bacteria Peptido- glycan layer Cell wall Plasma membrane 10 µm Gram-negative bacteria Outer membrane Peptido- glycan layer Plasma membrane Cell wall Carbohydrate portion of lipopolysaccharide (b) Gram-negative bacteria: crystal violet is easily rinsed away, revealing red dye.
  • 13.
    Figure 27.3a (a) Gram-positivebacteria: peptidoglycan traps crystal violet. Peptido- glycan layer Cell wall Plasma membrane
  • 14.
    Figure 27.3b Outer membrane Peptido- glycan layer Plasma membrane Cell wall Carbohydrateportion of lipopolysaccharide (b) Gram-negative bacteria: crystal violet is easily rinsed away, revealing red dye.
  • 15.
  • 16.
    • Many antibioticstarget peptidoglycan and damage bacterial cell walls • Gram-negative bacteria are more likely to be antibiotic resistant • A polysaccharide or protein layer called a capsule covers many prokaryotes © 2011 Pearson Education, Inc.
  • 17.
  • 18.
    • Some prokaryoteshave fimbriae, which allow them to stick to their substrate or other individuals in a colony • Pili (or sex pili) are longer than fimbriae and allow prokaryotes to exchange DNA © 2011 Pearson Education, Inc.
  • 19.
  • 20.
    Motility • In aheterogeneous environment, many bacteria exhibit taxis, the ability to move toward or away from a stimulus • Chemotaxis is the movement toward or away from a chemical stimulus © 2011 Pearson Education, Inc. Video: Prokaryotic Flagella (Salmonella typhimurium)
  • 21.
    • Most motilebacteria propel themselves by flagella scattered about the surface or concentrated at one or both ends • Flagella of bacteria, archaea, and eukaryotes are composed of different proteins and likely evolved independently © 2011 Pearson Education, Inc. Video: Prokaryotic Flagella (Salmonella typhimurium)
  • 22.
  • 23.
  • 24.
    Evolutionary Origins ofBacteria Flagella • Bacterial flagella are composed of a motor, hook, and filament • Many of the flagella’s proteins are modified versions of proteins that perform other tasks in bacteria • Flagella likely evolved as existing proteins were added to an ancestral secretory system • This is an example of exaptation, where existing structures take on new functions through descent with modification © 2011 Pearson Education, Inc.
  • 25.
    Internal Organization andDNA • Prokaryotic cells usually lack complex compartmentalization • Some prokaryotes do have specialized membranes that perform metabolic functions • These are usually infoldings of the plasma membrane © 2011 Pearson Education, Inc.
  • 26.
    Figure 27.7 (a) Aerobicprokaryote (b) Photosynthetic prokaryote Respiratory membrane Thylakoid membranes 0.2 µm 1 µm
  • 27.
    Figure 27.7a (a) Aerobicprokaryote Respiratory membrane 0.2 µm
  • 28.
    Figure 27.7b (b) Photosyntheticprokaryote Thylakoid membranes 1 µm
  • 29.
    • The prokaryoticgenome has less DNA than the eukaryotic genome • Most of the genome consists of a circular chromosome • The chromosome is not surrounded by a membrane; it is located in the nucleoid region • Some species of bacteria also have smaller rings of DNA called plasmids © 2011 Pearson Education, Inc.
  • 30.
  • 31.
    • There aresome differences between prokaryotes and eukaryotes in DNA replication, transcription, and translation • These allow people to use some antibiotics to inhibit bacterial growth without harming themselves © 2011 Pearson Education, Inc.
  • 32.
    Reproduction and Adaptation •Prokaryotes reproduce quickly by binary fission and can divide every 1–3 hours • Key features of prokaryotic reproduction: – They are small – They reproduce by binary fission – They have short generation times © 2011 Pearson Education, Inc.
  • 33.
    • Many prokaryotesform metabolically inactive endospores, which can remain viable in harsh conditions for centuries © 2011 Pearson Education, Inc.
  • 34.
  • 35.
    • Their shortgeneration time allows prokaryotes to evolve quickly – For example, adaptive evolution in a bacterial colony was documented in a lab over 8 years • Prokaryotes are not “primitive” but are highly evolved © 2011 Pearson Education, Inc.
  • 36.
    Figure 27.10 Daily serialtransfer 0.1 mL (population sample) Old tube (discarded after transfer) New tube (9.9 mL growth medium) EXPERIMENT RESULTS 1.8 Populationgrowthrate (relativetoancestralpopulation) 1.6 1.4 1.2 1.0 0 5,000 10,000 15,000 Generation 20,000
  • 37.
    Figure 27.10a Daily serialtransfer 0.1 mL (population sample) Old tube (discarded after transfer) New tube (9.9 mL growth medium) EXPERIMENT
  • 38.
  • 39.
    • Prokaryotes haveconsiderable genetic variation • Three factors contribute to this genetic diversity: – Rapid reproduction – Mutation – Genetic recombination Concept 27.2: Rapid reproduction, mutation, and genetic recombination promote genetic diversity in prokaryotes © 2011 Pearson Education, Inc.
  • 40.
    Rapid Reproduction andMutation • Prokaryotes reproduce by binary fission, and offspring cells are generally identical • Mutation rates during binary fission are low, but because of rapid reproduction, mutations can accumulate rapidly in a population • High diversity from mutations allows for rapid evolution © 2011 Pearson Education, Inc.
  • 41.
    Genetic Recombination • Geneticrecombination, the combining of DNA from two sources, contributes to diversity • Prokaryotic DNA from different individuals can be brought together by transformation, transduction, and conjugation • Movement of genes among individuals from different species is called horizontal gene transfer © 2011 Pearson Education, Inc.
  • 42.
    Transformation and Transduction •A prokaryotic cell can take up and incorporate foreign DNA from the surrounding environment in a process called transformation • Transduction is the movement of genes between bacteria by bacteriophages (viruses that infect bacteria) © 2011 Pearson Education, Inc.
  • 43.
  • 44.
  • 45.
  • 46.
  • 47.
    Conjugation and Plasmids •Conjugation is the process where genetic material is transferred between prokaryotic cells • In bacteria, the DNA transfer is one way • A donor cell attaches to a recipient by a pilus, pulls it closer, and transfers DNA • A piece of DNA called the F factor is required for the production of pili © 2011 Pearson Education, Inc.
  • 48.
  • 49.
    The F Factoras a Plasmid • Cells containing the F plasmid function as DNA donors during conjugation • Cells without the F factor function as DNA recipients during conjugation • The F factor is transferable during conjugation © 2011 Pearson Education, Inc.
  • 50.
    Figure 27.13 F plasmidBacterial chromosome F+ cell (donor) F− cell (recipient) Mating bridge Bacterial chromosome (a) Conjugation and transfer of an F plasmid Hfr cell (donor) F− cell (recipient) (b) Conjugation and transfer of part of an Hfr bacterial chromosome F factor A+ A− A+ A− A+ A+ A− F+ cell F+ cell A+A− Recombinant F− bacterium A+
  • 51.
  • 52.
  • 53.
  • 54.
    The F Factorin the Chromosome • A cell with the F factor built into its chromosomes functions as a donor during conjugation • The recipient becomes a recombinant bacterium, with DNA from two different cells © 2011 Pearson Education, Inc.
  • 55.
    Figure 27.13b-1 Hfr cell (donor) F− cell (recipient) (b)Conjugation and transfer of part of an Hfr bacterial chromosome F factor A− A+ A+ A− A+
  • 56.
    Figure 27.13b-2 Hfr cell (donor) F− cell (recipient) (b)Conjugation and transfer of part of an Hfr bacterial chromosome F factor A+ A+ A− A− A+ A+ A− A+
  • 57.
    Figure 27.13b-3 Hfr cell (donor) F− cell (recipient) (b)Conjugation and transfer of part of an Hfr bacterial chromosome F factor A+ A− Recombinant F− bacterium A+ A+ A− A− A+ A+ A− A+
  • 58.
    R Plasmids andAntibiotic Resistance • R plasmids carry genes for antibiotic resistance • Antibiotics kill sensitive bacteria, but not bacteria with specific R plasmids • Through natural selection, the fraction of bacteria with genes for resistance increases in a population exposed to antibiotics • Antibiotic-resistant strains of bacteria are becoming more common © 2011 Pearson Education, Inc.
  • 59.
    Concept 27.3: Diversenutritional and metabolic adaptations have evolved in prokaryotes • Prokaryotes can be categorized by how they obtain energy and carbon – Phototrophs obtain energy from light – Chemotrophs obtain energy from chemicals – Autotrophs require CO2 as a carbon source – Heterotrophs require an organic nutrient to make organic compounds © 2011 Pearson Education, Inc.
  • 60.
    • Energy andcarbon sources are combined to give four major modes of nutrition: – Photoautotrophy – Chemoautotrophy – Photoheterotrophy – Chemoheterotrophy © 2011 Pearson Education, Inc.
  • 61.
  • 62.
    The Role ofOxygen in Metabolism • Prokaryotic metabolism varies with respect to O2 – Obligate aerobes require O2 for cellular respiration – Obligate anaerobes are poisoned by O2 and use fermentation or anaerobic respiration – Facultative anaerobes can survive with or without O2 © 2011 Pearson Education, Inc.
  • 63.
    Nitrogen Metabolism • Nitrogenis essential for the production of amino acids and nucleic acids • Prokaryotes can metabolize nitrogen in a variety of ways • In nitrogen fixation, some prokaryotes convert atmospheric nitrogen (N2) to ammonia (NH3) © 2011 Pearson Education, Inc.
  • 64.
    Metabolic Cooperation • Cooperationbetween prokaryotes allows them to use environmental resources they could not use as individual cells • In the cyanobacterium Anabaena, photosynthetic cells and nitrogen-fixing cells called heterocysts (or heterocytes) exchange metabolic products © 2011 Pearson Education, Inc. Video: Cyanobacteria (Oscillatoria)
  • 65.
  • 66.
    • In someprokaryotic species, metabolic cooperation occurs in surface-coating colonies called biofilms © 2011 Pearson Education, Inc.
  • 67.
    Concept 27.4: Molecularsystematics is illuminating prokaryotic phylogeny • Until the late 20th century, systematists based prokaryotic taxonomy on phenotypic criteria • Applying molecular systematics to the investigation of prokaryotic phylogeny has produced dramatic results © 2011 Pearson Education, Inc.
  • 68.
    Lessons from MolecularSystematics • Molecular systematics led to the splitting of prokaryotes into bacteria and archaea • Molecular systematists continue to work on the phylogeny of prokaryotes © 2011 Pearson Education, Inc.
  • 69.
  • 70.
    • The useof polymerase chain reaction (PCR) has allowed for more rapid sequencing of prokaryote genomes • A handful of soil may contain 10,000 prokaryotic species • Horizontal gene transfer between prokaryotes obscures the root of the tree of life © 2011 Pearson Education, Inc.
  • 71.
    Archaea • Archaea sharecertain traits with bacteria and other traits with eukaryotes © 2011 Pearson Education, Inc.
  • 72.
  • 73.
  • 74.
    • Some archaealive in extreme environments and are called extremophiles • Extreme halophiles live in highly saline environments • Extreme thermophiles thrive in very hot environments © 2011 Pearson Education, Inc.
  • 75.
  • 76.
    • Methanogens livein swamps and marshes and produce methane as a waste product • Methanogens are strict anaerobes and are poisoned by O2 • In recent years, genetic prospecting has revealed many new groups of archaea • Some of these may offer clues to the early evolution of life on Earth © 2011 Pearson Education, Inc.
  • 77.
    Bacteria • Bacteria includethe vast majority of prokaryotes of which most people are aware • Diverse nutritional types are scattered among the major groups of bacteria © 2011 Pearson Education, Inc.
  • 78.
  • 79.
    Proteobacteria • These gram-negativebacteria include photoautotrophs, chemoautotrophs, and heterotrophs • Some are anaerobic, and others aerobic © 2011 Pearson Education, Inc.
  • 80.
    Figure 27.17-a Alpha Beta Gamma Delta Proteo- bacteria Epsilon Subgroup: AlphaProteobacteria Rhizobium (arrows) inside a root cell of a legume (TEM) 2.5µm Subgroup: Delta ProteobacteriaSubgroup: Gamma Proteobacteria Subgroup: Epsilon Proteobacteria Nitrosomonas (colorized TEM) 1µm Subgroup: Beta Proteobacteria 2µm 300µm Helicobacter pylori (colorized TEM)Fruiting bodies of Chondromyces crocatus, a myxobacterium (SEM) 200µm Thiomargarita namibiensis containing sulfur wastes (LM)
  • 81.
  • 82.
    Subgroup: Alpha Proteobacteria •Many species are closely associated with eukaryotic hosts • Scientists hypothesize that mitochondria evolved from aerobic alpha proteobacteria through endosymbiosis © 2011 Pearson Education, Inc.
  • 83.
    • Example: Rhizobium,which forms root nodules in legumes and fixes atmospheric N2 • Example: Agrobacterium, which produces tumors in plants and is used in genetic engineering © 2011 Pearson Education, Inc.
  • 84.
    Figure 27.17b Subgroup: AlphaProteobacteria Rhizobium (arrows) inside a root cell of a legume (TEM) 2.5µm
  • 85.
    Subgroup: Beta Proteobacteria •Example: the soil bacterium Nitrosomonas, which converts NH4 + to NO2 – © 2011 Pearson Education, Inc.
  • 86.
    Figure 27.17c Nitrosomonas (colorizedTEM) 1µm Subgroup: Beta Proteobacteria
  • 87.
    Subgroup: Gamma Proteobacteria •Examples include sulfur bacteria such as Chromatium and pathogens such as Legionella, Salmonella, and Vibrio cholerae • Escherichia coli resides in the intestines of many mammals and is not normally pathogenic © 2011 Pearson Education, Inc.
  • 88.
    Figure 27.17d Subgroup: GammaProteobacteria 200µm Thiomargarita namibiensis containing sulfur wastes (LM)
  • 89.
    Subgroup: Delta Proteobacteria •Example: the slime-secreting myxobacteria © 2011 Pearson Education, Inc.
  • 90.
    Figure 27.17e Subgroup: DeltaProteobacteria 300µm Fruiting bodies of Chondromyces crocatus, a myxobacterium (SEM)
  • 91.
    Subgroup: Epsilon Proteobacteria •This group contains many pathogens including Campylobacter, which causes blood poisoning, and Helicobacter pylori, which causes stomach ulcers © 2011 Pearson Education, Inc.
  • 92.
    Figure 27.17f Subgroup: EpsilonProteobacteria 2µm Helicobacter pylori (colorized TEM)
  • 93.
    Figure 27.17-b Chlamydias 5µm Spirochetes 2.5µm Leptospira,a spirochete (colorized TEM) Gram-Positive Bacteria 2µm 5µm Hundreds of mycoplasmas covering a human fibroblast cell (colorized SEM) Streptomyces, the source of many antibiotics (SEM) 40µm Oscillatoria, a filamentous cyanobacterium Cyanobacteria Chlamydia (arrows) inside an animal cell (colorized TEM)
  • 94.
    Chlamydias • These bacteriaare parasites that live within animal cells • Chlamydia trachomatis causes blindness and nongonococcal urethritis by sexual transmission © 2011 Pearson Education, Inc.
  • 95.
    Figure 27.17g Chlamydias 2.5µm Chlamydia (arrows)inside an animal cell (colorized TEM)
  • 96.
    Spirochetes • These bacteriaare helical heterotrophs • Some are parasites, including Treponema pallidum, which causes syphilis, and Borrelia burgdorferi, which causes Lyme disease © 2011 Pearson Education, Inc.
  • 97.
  • 98.
    Cyanobacteria • These arephotoautotrophs that generate O2 • Plant chloroplasts likely evolved from cyanobacteria by the process of endosymbiosis © 2011 Pearson Education, Inc.
  • 99.
    Figure 27.17i 40µm Oscillatoria, afilamentous cyanobacterium Cyanobacteria
  • 100.
    Gram-Positive Bacteria • Gram-positivebacteria include – Actinomycetes, which decompose soil – Bacillus anthracis, the cause of anthrax – Clostridium botulinum, the cause of botulism – Some Staphylococcus and Streptococcus, which can be pathogenic – Mycoplasms, the smallest known cells © 2011 Pearson Education, Inc.
  • 101.
    Figure 27.17j Gram-Positive Bacteria 5µm Streptomyces,the source of many antibiotics (SEM)
  • 102.
    Figure 27.17k Gram-Positive Bacteria 2µm Hundredsof mycoplasmas covering a human fibroblast cell (colorized SEM)
  • 103.
    Concept 27.5: Prokaryotesplay crucial roles in the biosphere • Prokaryotes are so important that if they were to disappear the prospects for any other life surviving would be dim © 2011 Pearson Education, Inc.
  • 104.
    Chemical Recycling • Prokaryotesplay a major role in the recycling of chemical elements between the living and nonliving components of ecosystems • Chemoheterotrophic prokaryotes function as decomposers, breaking down dead organisms and waste products • Prokaryotes can sometimes increase the availability of nitrogen, phosphorus, and potassium for plant growth © 2011 Pearson Education, Inc.
  • 105.
    Figure 27.18 Seedlings grow- ingin the lab Strain 3Strain 2 0 No bacteria Soil treatment 0.2 0.4 0.6 0.8 1.0 UptakeofKbyplants(mg) Strain 1
  • 106.
  • 107.
    • Prokaryotes canalso “immobilize” or decrease the availability of nutrients © 2011 Pearson Education, Inc.
  • 108.
    Ecological Interactions • Symbiosisis an ecological relationship in which two species live in close contact: a larger host and smaller symbiont • Prokaryotes often form symbiotic relationships with larger organisms © 2011 Pearson Education, Inc.
  • 109.
    • In mutualism,both symbiotic organisms benefit • In commensalism, one organism benefits while neither harming nor helping the other in any significant way • In parasitism, an organism called a parasite harms but does not kill its host • Parasites that cause disease are called pathogens © 2011 Pearson Education, Inc.
  • 110.
  • 111.
    • The ecologicalcommunities of hydrothermal vents depend on chemoautotropic bacteria for energy © 2011 Pearson Education, Inc.
  • 112.
    Concept 27.6: Prokaryoteshave both beneficial and harmful impacts on humans • Some prokaryotes are human pathogens, but others have positive interactions with humans © 2011 Pearson Education, Inc.
  • 113.
    Mutualistic Bacteria • Humanintestines are home to about 500–1,000 species of bacteria • Many of these are mutalists and break down food that is undigested by our intestines © 2011 Pearson Education, Inc.
  • 114.
    Pathogenic Bacteria • Prokaryotescause about half of all human diseases – For example, Lyme disease is caused by a bacterium and carried by ticks © 2011 Pearson Education, Inc.
  • 115.
  • 116.
  • 117.
  • 118.
  • 119.
    • Pathogenic prokaryotestypically cause disease by releasing exotoxins or endotoxins • Exotoxins are secreted and cause disease even if the prokaryotes that produce them are not present • Endotoxins are released only when bacteria die and their cell walls break down © 2011 Pearson Education, Inc.
  • 120.
    • Horizontal genetransfer can spread genes associated with virulence • Some pathogenic bacteria are potential weapons of bioterrorism © 2011 Pearson Education, Inc.
  • 121.
    Prokaryotes in Researchand Technology • Experiments using prokaryotes have led to important advances in DNA technology – For example, E. coli is used in gene cloning – For example, Agrobacterium tumefaciens is used to produce transgenic plants • Bacteria can now be used to make natural plastics © 2011 Pearson Education, Inc.
  • 122.
    • Prokaryotes arethe principal agents in bioremediation, the use of organisms to remove pollutants from the environment • Bacteria can be engineered to produce vitamins, antibiotics, and hormones • Bacteria are also being engineered to produce ethanol from waste biomass © 2011 Pearson Education, Inc.
  • 123.
  • 124.
  • 125.
  • 126.
  • 127.
    Figure 27.UN03 Fimbriae Cell wall Circular chromosome Sexpilus Flagella Internal organization Capsule
  • 128.
  • 129.

Editor's Notes

  • #4 Figure 27.1 Why is this lake’s water pink?
  • #7 Figure 27.2 The most common shapes of prokaryotes.
  • #8 Figure 27.2 The most common shapes of prokaryotes.
  • #9 Figure 27.2 The most common shapes of prokaryotes.
  • #10 Figure 27.2 The most common shapes of prokaryotes.
  • #13 Figure 27.3 Gram staining.
  • #14 Figure 27.3 Gram staining.
  • #15 Figure 27.3 Gram staining.
  • #16 Figure 27.3 Gram staining.
  • #18 Figure 27.4 Capsule.
  • #20 Figure 27.5 Fimbriae.
  • #23 Figure 27.6 A prokaryotic flagellum.
  • #24 Figure 27.6 A prokaryotic flagellum.
  • #27 Figure 27.7 Specialized membranes of prokaryotes.
  • #28 Figure 27.7 Specialized membranes of prokaryotes.
  • #29 Figure 27.7 Specialized membranes of prokaryotes.
  • #31 Figure 27.8 A prokaryotic chromosome and plasmids.
  • #35 Figure 27.9 An endospore.
  • #37 Figure 27.10 Inquiry: Can prokaryotes evolve rapidly in response to environmental change?
  • #38 Figure 27.10 Inquiry: Can prokaryotes evolve rapidly in response to environmental change?
  • #39 Figure 27.10 Inquiry: Can prokaryotes evolve rapidly in response to environmental change?
  • #44 Figure 27.11 Transduction.
  • #45 Figure 27.11 Transduction.
  • #46 Figure 27.11 Transduction.
  • #47 Figure 27.11 Transduction.
  • #49 Figure 27.12 Bacterial conjugation.
  • #51 Figure 27.13 Conjugation and recombination in E. coli.
  • #52 Figure 27.13 Conjugation and recombination in E. coli.
  • #53 Figure 27.13 Conjugation and recombination in E. coli.
  • #54 Figure 27.13 Conjugation and recombination in E. coli.
  • #56 Figure 27.13 Conjugation and recombination in E. coli.
  • #57 Figure 27.13 Conjugation and recombination in E. coli.
  • #58 Figure 27.13 Conjugation and recombination in E. coli.
  • #62 Table 27.1 Major Nutritional Modes
  • #66 Figure 27.14 Metabolic cooperation in a prokaryote.
  • #70 Figure 27.15 A simplified phylogeny of prokaryotes.
  • #73 Figure 27.UN01 In-text figure, p. 566
  • #74 Table 27.2 A Comparison of the Three Domains of Life
  • #76 Figure 27.16 Extreme thermophiles.
  • #79 Figure 27.UN02 In-text figure, p. 567
  • #81 Figure 27.17 Exploring: Major Groups of Bacteria
  • #82 Figure 27.17 Exploring: Major Groups of Bacteria
  • #85 Figure 27.17 Exploring: Major Groups of Bacteria
  • #87 Figure 27.17 Exploring: Major Groups of Bacteria
  • #89 Figure 27.17 Exploring: Major Groups of Bacteria
  • #91 Figure 27.17 Exploring: Major Groups of Bacteria
  • #93 Figure 27.17 Exploring: Major Groups of Bacteria
  • #94 Figure 27.17 Exploring: Major Groups of Bacteria
  • #96 Figure 27.17 Exploring: Major Groups of Bacteria
  • #98 Figure 27.17 Exploring: Major Groups of Bacteria
  • #100 Figure 27.17 Exploring: Major Groups of Bacteria
  • #102 Figure 27.17 Exploring: Major Groups of Bacteria
  • #103 Figure 27.17 Exploring: Major Groups of Bacteria
  • #106 Figure 27.18 Impact of bacteria on soil nutrient availability.
  • #107 Figure 27.18 Impact of bacteria on soil nutrient availability.
  • #111 Figure 27.19 Mutualism: bacterial “headlights.”
  • #116 Figure 27.20 Lyme disease.
  • #117 Figure 27.20 Lyme disease.
  • #118 Figure 27.20 Lyme disease.
  • #119 Figure 27.20 Lyme disease.
  • #124 Figure 27.21 Some applications of prokaryotes.
  • #125 Figure 27.21 Some applications of prokaryotes.
  • #126 Figure 27.21 Some applications of prokaryotes.
  • #127 Figure 27.21 Some applications of prokaryotes.
  • #128 Figure 27.UN03 Summary figure, Concept 27.1
  • #129 Figure 27.UN04 Test Your Understanding, question 8
  • #130 Figure 27.UN05 Appendix A: answer to Test Your Understanding, question 8