Microbial Diversity Bacteria Archaea Protista Fungi
Figure 19-1 Three common prokaryote shapes
Figure 19-2 The prokaryote flagellum
Figure 19-2b The structure of the bacterial flagellum cell wall wheelandaxle base outer membrane peptidoglycan layer plasma membrane (b) The structure of the bacterial flagellum
Figure 19-3 The cause of tooth decay
Figure 19-4 Spores protect some bacteria
Figure 19-5 Some prokaryotes thrive in extreme conditions
Figure 19-6 Cyanobacteria
Figure 19-7 Reproduction in prokaryotes
Figure 19-8 Conjugation: prokaryotic mating
Figure 19-9 Nitrogen-fixing bacteria in root nodules
Figure 19-10 The sizes of microorganisms 1 m Staphylococcus cyanobacterium Escherichia coli Eukaryotic cells (10 100 m) Prokaryotic cells (0.2 10 m) Viruses (0.05 0.2 m)
Viruses RNA or DNA Can have a membrane Plant viruses vs. animal viruses
Figure 19-11b Bacteriophage
Figure 19-13 Some viruses infect bacteria
Figure 19-11a Rabies virus
Figure 19-11c Tobacco mosaic viruses
Figure 19-11d Influenza viruses
Figure 19-12 Viral structure and replication glycoproteins envelope (lipid bilayer) protein coat spikes genetic material (viral RNA) coated with protein core proteins reverse transcriptase
Figure E19-2 How viruses replicate Step 2 envelope coat core RNA reverse transcriptase 1 A virus attaches to a receptor on the host's plasma membrane; its core disintegrates, and viral RNA enters the cytoplasm (nucleus) (cytoplasm) DNA RNA mrna (a) HIV virus, a retrovirus, invades a white blood cell
Figure E19-2 How viruses replicate Step 8 envelope coat (cytoplasm) DNA DNA 1 A virus enters a cell by endocytosis mrna (nucleus) (b) Herpes virus, a double-stranded DNA virus, invades a skin cell
Figure 19-14 Prions: puzzling proteins
Table 20-1 The Major Groups of Protists (1 of 2) Group Subgroup Locomotion Nutrition Representative Features Representative Genus Excavates Diplomonads Swim with flagella Heterotrophic Lack mitochondria; inhabit soil or water, or may be parasitic Giardia (intestinal parasite of mammals) Parabasalids Swim with flagella Heterotrophic Lack mitochondria; parasites or commensal symbionts Trichomonas (causes the sexually transmitted infection trichomoniasis) Euglenozoans Euglenids Swim with one flagellum Autotrophic; photosynthetic Have an eyespot; all fresh water Euglena (common pond-dweller) Kinetoplastids Swim with flagella Heterotrophic Inhabit soil or water, or may be parasitic Trypanosoma (causes African sleeping sickness) Stramenopiles (chromists) Water molds Swim with flagella (gametes) Heterotrophic Filamentous Plasmopara (causes downy mildew) Diatoms Glide along surfaces Autotrophic; photosynthetic Have silica shells; most marine Navicula (glides toward light) Brown algae Nonmotile Autotrophic; photosynthetic Seaweeds of temperate oceans Macrocystis (forms kelp forests) Alveolates Dinoflagellates Swim with two flagella Autotrophic; photosynthetic Many bioluminescent; often have cellulose Apicomplexans Nonmotile Heterotrophic All parasitic; form infectious spores Ciliates Swim with cilia Heterotrophic Include the most complex single cells Gonyaulax (causes red tide) Plasmodium (causes malaria) Paramecium (fastmoving pond-dweller)
Table 20-1 The Major Groups of Protists (2 of 2) Group Subgroup Locomotion Nutrition Representative Features Representative Genus Rhizarians Foraminiferans Extend thin pseudopods Heterotrophic Have calcium carbonate shells Globigerina Radiolarians Extend thin pseudopods Heterotrophic Have silica shells Actinomma Amoebozoans Lobose amoebas Extend thick pseudopods Heterotrophic Have no shells Amoeba (common pond-dweller) Acellular slime molds Sluglike mass oozes over surfaces Heterotrophic Form multinucleate plasmodium Physarum (forms a large, bright orange mass) Cellular slime molds Amoeboid cells extend pseudopods; sluglike mass crawls over surfaces Heterotrophic Form pseudoplasmodium with individual amoeboid cells Dictyostelium (often used in laboratory studies) Red algae Nonmotile Autotrophic; photosynthetic Some deposit calcium Porphyra (used to carbonate; mostly marine make sushi wrappers) Green algae Swim with flagella (some species) Autotrophic; photosynthetic Closest relatives of land plants Ulva (sea lettuce)
Figure 20-1 Pseudopods
Figure 20-2a Reproducing by cell division
Figure 20-2b Exchanging genetic material
Figure 20-3 Giardia: The curse of campers
Figure 20-4 Trichomonas causes a sexually transmitted infection
Figure 20-5 Euglena, a representative euglenid flagellum eyespot contractile vacuole stored food nucleolus chloroplasts nucleus
Figure 20-6 A disease-causing kinetoplastid
Figure 20-8 Some representative diatoms
Figure 20-9 Brown algae, a multicellular protist
Figure 20-10 A dinoflagellate
Figure 20-11 A red tide
Figure 20-12 The life cycle of the malaria parasite 1 A female Anopheles mosquito bites an infected human and ingests gametocytes, which become gametes (infected human) female gametocyte male gamete female gamete salivary glands male gametocyte 2 Fertilization produces a zygote that enters the wall of the mosquito s stomach 3 The zygote gives rise to sporozoites that migrate to the mosquito s salivary glands 7 The synchronized rupture of red blood cells releases toxins and the parasites; some parasites infect more blood cells 6 Parasites multiply in the red blood cells 8 Some parasites become gametocytes, which may be ingested by another feeding Anopheles mosquito 5 Parasites emerge from the liver and enter red blood cells 4 The infected mosquito bites an uninfected human and saliva containing sporozites is injected; the sporozites enter the liver and develop through several stages liver
Figure 20-13 The complexity of ciliates macronucleus oral groove food vacuole forming micronucleus food vacuole contractile vacuole anal pore cilia
Figure 20-14 A microscopic predator
Figure 20-15a Foraminifera
Figure 20-15b A radiolarian
Figure 20-16 An amoeba
Figure 20-17a Plasmodium
Figure 20-17b Fruiting bodies
Figure 20-18 The life cycle of a cellular slime mold 1 When food becomes scarce, cells aggregate into a slug-like mass called a pseudoplasmodium nucleus fruiting bodies 3 Single, amoeba-like cells emerge from spores, and crawl and feed spores 2 A pseudoplasmodium migrates toward light and forms a fruiting body in which spores are produced haploid (n)
Figure 20-19 Red algae
Figure 20-20a Spirogyra
Figure 20-20b Ulva
Figure E19-1 Rare beef is a haven for dangerous bacteria
Figure 20-20 Green algae
Table 20-1 The Major Groups of Protists