Campbell Biology Tenth Edition: Bacteria and Archaea Lecture Notes PDF

CAMPBELL BIOLOGY TENTH EDITION Reece Urry Cain Wasserman Minorsky Jackson 27 Bacteria and Archaea Lecture...

CAMPBELL BIOLOGY TENTH EDITION Reece Urry Cain Wasserman Minorsky Jackson 27 Bacteria and Archaea Lecture Presentation by Nicole Tunbridge and Kathleen Fitzpatrick 1 © 2014 Pearson Education, Inc. Get out your note cards! ▪ Use your resources to create note cards for the following terms/ideas: 1. Prokaryote 2. Peptidoglycan 3. Symbiosis 4. Horizontal gene transfer 5. Bioremediation ▪ You may want to write in pencil and leave yourself some room so you can add/subtract later 2 © 2014 Pearson Education, Inc.  ▪ Each branch point on the phylogenetic tree represents the divergence of two species from a common ancestor ▪ “Common Ancestor” is sometimes abbreviated C.A. ▪ Sister taxa are groups that share an immediate common ancestor ▪ These are sisters to each other and “cousins” to the other taxa from that common ancestor 3 © 2014 Pearson Education, Inc. Figure 26.5 Branch point: where lineages diverge Taxon A 3 Taxon B Sister 4 taxa Taxon C 2 Taxon D 5 Taxon E ANCESTRAL 1 LINEAGE Taxon F Basal Taxon G taxon This branch point This branch point forms represents the a polytomy: more than two common ancestor of branches emerge from this taxa A–G. point. 4 © 2014 Pearson Education, Inc.  ▪ A rooted tree includes a branch to represent the last common ancestor of all taxa in the tree ▪ Shows the “great grandma” ▪ A basal taxon diverges early in the history of a group and originates near the common ancestor of the group ▪ A polytomy is a branch from which more than two groups emerge 5 © 2014 Pearson Education, Inc. What We Can and Cannot Learn from Phylogenetic Trees 1. Phylogenetic trees show patterns of descent, not phenotypic similarity 2. Phylogenetic trees do not indicate when species evolved or how much change occurred in a lineage ▪ Trees DO indicate patterns 3. It should not be assumed that a taxon “evolved from” the taxon next to it ▪ They both evolved from a common ancestor 6 © 2014 Pearson Education, Inc. Figure 26.3 Cell division error Species: Panthera pardus Genus: Panthera Family: Felidae Order: Carnivora Class: Mammalia Phylum: Chordata Domain: Kingdom: Bacteria Animalia Domain: Archaea Domain: Eukarya 7 © 2014 Pearson Education, Inc.  Learning Objectives in Chapter 27 1. Understand structural and functional prokaryote features 2. Be able to define symbiosis and give examples 3. Know the effects of rapid prokaryote reproduction 4. Describe how prokaryotes play crucial roles in the biosphere 8 © 2014 Pearson Education, Inc. Concept 1: Structural and functional prokaryote features 9 © 2014 Pearson Education, Inc.  ▪ 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 10 © 2014 Pearson Education, Inc. Structural and functional adaptations contribute to prokaryotic success ▪ Earth’s first organisms were likely prokaryotes ▪ They are thought to be 3.5 billion years old ▪ Most prokaryotes are unicellular, although some species form colonies ▪ They’re subject to natural selection 11 © 2014 Pearson Education, Inc.  Most prokaryotic cells are much smaller than eukaryotic cells Prokaryotic cells have a variety of shapes The three most common shapes are spheres (cocci), rods (bacilli), and spirals 1 µm 1 µm 3 µm 12 © 2014 Pearson Education, Inc. (a) Spherical (b) Rod-shaped (c) Spiral Figure 27.4 Bacterial Bacterial capsule cell wall Tonsil cell 200 nm 13 © 2014 Pearson Education, Inc. Prokaryotic Cell-Surface Structures ▪ An important feature of nearly all prokaryotic cells is their cell wall ▪ This is a feature outside of the cell membrane, that animal cells do not have ▪ It maintains cell shape, protects the cell, and prevents it from bursting in high-water environments 14 © 2014 Pearson Education, Inc. Prokaryotic Cell-Surface Structures ▪ Bacterial cell walls contain peptidoglycan, a network of sugar polymers cross-linked by polypeptides ▪ Archaea contain polysaccharides and proteins but lack peptidoglycan 15 © 2014 Pearson Education, Inc.  ▪ Scientists use the Gram stain to classify bacteria by cell wall composition ▪ Gram-positive bacteria have a single cell membrane with a large amount of peptidoglycan ▪ Gm + cells look purple in a gram stain 16 © 2014 Pearson Education, Inc. Figure 27.3 (b) Gram-negative bacteria (a) Gram-positive bacteria Carbohydrate portion of lipopolysaccharide Peptido- Outer Cell glycan Cell membrane wall layer wall Peptido- Plasma glycan layer membrane Plasma membrane Peptidoglycan traps crystal violet, Crystal violet is easily rinsed away, revealing which masks the safranin dye. the red safranin dye. Gram-positive Gram-negative bacteria bacteria 10 µm 17 © 2014 Pearson Education, Inc.  ▪ Scientists use the Gram stain to classify bacteria by cell wall composition ▪ Gram-negative bacteria have less peptidoglycan and it’s sandwiched between two cell membranes; the outer membrane can be toxic ▪ Gm – cells look red when gram stained 18 © 2014 Pearson Education, Inc. Figure 27.3 (a) Gram-positive bacteria (b) Gram-negative bacteria Carbohydrate portion of lipopolysaccharide Peptido- Outer Cell glycan Cell membrane wall layer wall Peptido- Plasma glycan layer membrane Plasma membrane Peptidoglycan traps crystal violet, Crystal violet is easily rinsed away, revealing which masks the safranin dye. the red safranin dye. Gram-positive Gram-negative bacteria bacteria 10 µm 19 © 2014 Pearson Education, Inc.  ▪ Many antibiotics target peptidoglycan and damage bacterial cell walls ▪ Why don’t antibiotics harm human cells? 20 © 2014 Pearson Education, Inc.  ▪ Sometimes a polysaccharide or protein layer called a capsule can be produced – it covers many prokaryotes ▪ This can be sticky/slimy and allow the cell to ‘glue’ onto things ▪ The capsule is the most exterior layer – it’s outside of the cell wall, which is outside of the cell membrane 21 © 2014 Pearson Education, Inc. Figure 27.4 Bacterial Bacterial capsule cell wall Tonsil cell 200 nm 22 © 2014 Pearson Education, Inc.  ▪ Many prokaryotes also form endospores ▪ Sometimes just called spores, they’re a structure that allows the cell to “hibernate” ▪ It can hibernate, remaining viable in harsh conditions for centuries, until it’s triggered to reactivate 23 © 2014 Pearson Education, Inc. Figure 27.5 Endospore Coat 0.3 µm 24 © 2014 Pearson Education, Inc.  ▪ 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 ▪ Both of these adaptations are very common in bacteria 25 © 2014 Pearson Education, Inc. Figure 27.6 Fimbriae 1 µm 26 © 2014 Pearson Education, Inc.  ▪ Most bacteria propel themselves by flagella scattered about the surface or concentrated at one or both ends ▪ These often look like tails; the most common example is on human sperm cells ▪ Flagella of bacteria, archaea, and eukaryotes are composed of different proteins and likely evolved independently 27 © 2014 Pearson Education, Inc. Figure 27.7 Flagellum Filament 20 nm Hook Cell wall Motor Plasma Peptidoglycan membrane Rod layer 28 © 2014 Pearson Education, Inc.  ▪ The prokaryotic genome has less DNA than the eukaryotic genome ▪ The DNA is not inside a nucleus like in eukaryotic cells; it is located in a nucleoid region ▪ Some species of bacteria also have smaller rings of DNA called plasmids 29 © 2014 Pearson Education, Inc. Figure 27.9 Chromosome Plasmids 1 µm 30 © 2014 Pearson Education, Inc. Concept 2: Symbiosis 31 © 2014 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 32 © 2014 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 33 © 2014 Pearson Education, Inc.  Symbiotic Emoji-lationship Host Symbiont Relationship (Host/Symbiont) Commensalism 0 + / Mutualism + + / Parasitism - + / 34 © 2014 Pearson Education, Inc.  Symbiotic Emoji-lationship Host Symbiont Relationship (Host/Symbiont) Commensalism 0 + / Mutualism + + / Parasitism - + / 35 © 2014 Pearson Education, Inc. Concept 3: How prokaryote populations are affected by their rapid reproduction 36 © 2014 Pearson Education, Inc. Reproduction ▪ Prokaryotes reproduce quickly by binary fission and can divide every 1–3 hours ▪ What does “Binary fission” mean? ▪ Offspring are genetically identical ▪ Key features of prokaryotic reproduction 1. They are small 2. They reproduce by binary fission 3. They have short generation times 37 © 2014 Pearson Education, Inc. Rapid reproduction, mutation, and genetic recombination promote genetic diversity in prokaryotes ▪ Prokaryotes have considerable genetic variation ▪ Three factors contribute to this genetic diversity 1. Rapid reproduction ▪ Their short generation time allows prokaryotes to evolve quickly ▪ Prokaryotes are not “primitive” but are highly evolved 2. Mutation 3. Genetic recombination 38 © 2014 Pearson Education, Inc. Genetic Recombination ▪ Genetic recombination, the combining of DNA from two individuals, contributes to diversity ▪ Prokaryotic DNA from two different individuals can be brought together by 1. transformation, 2. transduction, and 3. conjugation ▪ Movement of genes among individuals from different species is called horizontal gene transfer 39 © 2014 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) 40 © 2014 Pearson Education, Inc.  41 © 2014 Pearson Education, Inc. 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 42 © 2014 Pearson Education, Inc. Figure 27.12 Sex pilus 1 µm 43 © 2014 Pearson Education, Inc. The F Factor as a Plasmid ▪ The F factor, the name of a trait, is present in a small piece of DNA called the F plasmid ▪ Cells containing the F plasmid in their DNA function as DNA donors during conjugation ▪ Cells without the F factor function as DNA recipients during conjugation ▪ The F factor is transferable during conjugation ▪ The recipient becomes a recombinant bacterium, with DNA from two different cells ▪ Its DNA has “recombined” 44 © 2014 Pearson Education, Inc. Figure 27.13 Bacterial F plasmid chromosome F+ cell F+ cell (donor) Mating bridge F− cell (recipient) Bacterial F+ cell chromosome (a) Conjugation and transfer of an F plasmid Hfr cell (donor) A+ A+ A+ A+ A− A+ F factor A− A− A+ A− Recombinand − F cell F− bacterium (recipient) (b) Conjugation and transfer of part of an Hfr bacterial chromosome, resulting in recombination 45 © 2014 Pearson Education, Inc. Prokaryotic 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 ▪ Prokaryotes can form their own Nitrogen ▪ We call this “nitrogen fixation” ▪ Nitrogen is essential for the production of amino acids and nucleic acids 46 © 2014 Pearson Education, Inc. Figure 27.15 Eukarya Domain Eukaryotes Korarchaeotes Domain Archaea Euryarchaeotes Crenarchaeotes UNIVERSAL Nanoarchaeotes ANCESTOR Proteobacteria Domain Bacteria Chlamydias Spirochetes Cyanobacteria Gram-positive bacteria 47 © 2014 Pearson Education, Inc. An Overview of Prokaryotic Diversity ▪ Genetic analysis lead to the division of prokaryotes into two domains, Bacteria and Archaea ▪ These bacterial domain is divided into 6 major groups: 1. Proteobacteria 2. Green bacteria 3. Chlamydias 4. Spirochetes 5. Cyanobacteria 6. Gram-positive bacteria 48 © 2014 Pearson Education, Inc. Proteobacteria ▪ These gram-negative bacteria are also called ”purple bacteria” and are characterized by being: ▪ Photosynthetic ▪ Nitrogen-fixing ▪ Disease causing Green bacteria ▪ These prokaryotes are characterized by being: ▪ Photosynthetic ▪ Present in extreme conditions such as salt water or hot springs © 2014 Pearson Education, Inc. 49  Chlamydias ▪ These bacteria are parasites that live within animal cells and are disease-causing ▪ Chlamydia trachomatis causes blindness and nongonococcal urethritis by sexual transmission Chlamydia (arrows) inside an animal cell (colorized TEM) 2.5 µm 50 © 2014 Pearson Education, Inc. Spirochetes ▪ These bacteria are endoflagellated - they have a propeller built into their body ▪ Some are parasites, and these are often disease causing ▪ Treponema pallidum causes syphilis, Borrelia burgdorferi causes Lyme disease Leptospira, a spirochete ▪ Other spirochetes digest wood 5 µm 51 © 2014 Pearson Education, Inc. Figure 27.20 5 µm 52 © 2014 Pearson Education, Inc.  Cyanobacteria ▪ These are photosynthetic bacteria that generate O2 ▪ Plant chloroplasts likely evolved from cyanobacteria by the process of endosymbiosis ▪ These are often aquatic producers and nitrogen fixers Oscillatoria, a filamentous cyanobacterium 40 µm 53 © 2014 Pearson Education, Inc.  Gram-Positive Bacteria ▪ Gram-positive bacteria can be disease causing and 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 54 © 2014 Pearson Education, Inc.  Figure 27.16bd Gram-positive bacteria Streptomyces, the source of many antibiotics (SEM) 5 µm Gram-positive bacteria Hundreds of mycoplasmas covering a human fibroblast cell (colorized SEM) 2 µm Figure 27.16be 55 © 2014 Pearson Education, Inc.  Archaea ▪ It’s not an accident that “archaea” sounds like “archaic” ▪ Archaea share certain traits with bacteria and other traits with eukaryotes 56 © 2014 Pearson Education, Inc.  ▪ Some archaea live in extreme environments and are called extremophiles ▪ Extreme halophiles live in highly saline environments ▪ Extreme thermophiles thrive in very hot environments 57 © 2014 Pearson Education, Inc. Figure 27.17 58 © 2014 Pearson Education, Inc.  ▪ Methanogens live in swamps and marshes and produce methane as a waste product ▪ Methanogens are strict anaerobes and are poisoned by O2 ▪ Some of these may offer clues to the early evolution of life on Earth 59 © 2014 Pearson Education, Inc. Concept 4: The many roles of prokaryotes in the biosphere 60 © 2014 Pearson Education, Inc. Disadvantages of Prokaryotes ▪ They can “immobilize” or decrease the availability of nutrients in the soil ▪ They cause half of all human disease ▪ Exotoxins are proteins secreted by bacteria which cause cholera, tetanus and botulism ▪ Endotoxins are released when bacteria die and are the reason why bacteria like Salmonella species and and can make us so sick 61 © 2014 Pearson Education, Inc. Disadvantages of Prokaryotes ▪ Some can be used in biological warfare (ex: Anthrax) ▪ Food Spoilage ▪ Horizontal gene transfer allows bacteria that are naturally antibiotic resistant to transfer genes for resistance to others 62 © 2014 Pearson Education, Inc. 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. They: ▪ Are important recyclers of chemicals ▪ Are decomposers of waste and dead organisms ▪ Can convert nitrogen, phosphorus, and potassium into useable forms and encourage plant growth ▪ Are present in the intestinal tract in almost every living organism, helping with digestion and nutrient absorption 63 © 2014 Pearson Education, Inc.  ▪ Prokaryotes are the “active ingredients” in bioremediation, the use of organisms to remove pollutants from the environment ▪ Bacteria can be engineered to produce vitamins, antibiotics, and hormones 64 © 2014 Pearson Education, Inc. Figure 27.22  ▪ Bacteria are also being engineered to produce ethanol from agricultural and municipal waste biomass, switchgrass, and corn Figure 27.23 65 © 2014 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 66 © 2014 Pearson Education, Inc. For Next Lecture: 1. Remember to bring notecards to (every) class 2. Do Chapter 27 HW in blackboard 3. Do Chapter 27 Quiz in blackboard 4. Read Ch 27 if needed 67 © 2014 Pearson Education, Inc.