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62 Cards in this Set
- Front
- Back
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Biological classification(8)
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Domain
Kingdom Phylum Class Order Family Genus Species |
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Scientific nomenclature
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Binomial nomenclature
Each organism designated by two names Genus Specific epithet Species names Latinized Underlined or italics Genus name is capitalized; not specific epithet Example: Escherichia coli Homo sapiens |
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Methods of classification
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Numerical taxonomy
equal weight to all characters measure many characters many strains calculate percentage shared characters similarity coefficient (SJ) dendograms illustrate relationships |
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Traditional Methods
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Morphology
shape cocci, bacilli, spirilla arrangement singly, chains, clusters flagella arrangement Gram reaction gram-positive, gram-negative |
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Traditional Methods
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Biochemical and Physiological
growth requirements end products enzymes produced carbon source oxidation/reduction measurement tetrazolium dye fermentation properties acids, gases |
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Traditional Methods
Viruses that infect bacteria are called |
Serology
antibodies highly specific for target molecules distinguish between closely related strain differentiation Phage typing viruses that infect bacteria pattern of strains attacked by specific phage host range of phage is narrow |
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Genomic methods: Percent G+C
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Fraction of guanine-cytosine pairs
melting point of DNA density measurements % G+C indicate relatedness values vary similarities do not prove relatedness |
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Genomic methods:
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Hybridization
DNA hybridization heat DNA to separate strands single strands from different sources are mixed anneal in certain regions amount of annealing determined by genetic relatedness |
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Genomic methods: Probes
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Probe is tagged
fluorescent dye chemiluminescent molecule radioactive elements specific for certain organism cell DNA is lysed anneal in certain regions amount of annealing determined by genetic relatedness |
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Ribosomal RNA as probe
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Isolate rRNA from cell
Add DNA primer Reverse transcriptase makes cDNA Destroys RNA Duplicate ssDNA RNA Polymerase Multiple rRNA copies of dsDNA |
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Genomic methods: Sequence
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DNA Sequencing
ultimate tool of taxonomy genome sequencing most accurate formidable task--large size of genomes 4.5 million base pairs in E. coli Ribosomal RNA genes small ribosomal subunit all cellular organisms contain rRNA evolves more slowly highly conserved Protein encoding genes |
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Dichotomous keys
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Series of questions
General questions Divide into larger groups Specific questions Result in smaller groups |
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The genealogical tree of prokaryotes is divided into two domains _________________
& __________________. Domain ____________________ (contains twenty-three phyla) |
Prokaryotic genealogical tree
Based on 16S ribosomal RNA Two domains Archaea Two phyla Bacteria 23 phyla |
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Domain ___________________ (contains two major phyla)
1.._____________________ - 2.._____________________ - |
A1 Crenarchaeota
One class Morphologically diverse Metabolically diverse A2 Euryarchaeota Five classes Methanogens Extreme halophiles Thermoacidophiles |
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Domain Bacteria
I. _____________________________________ A. B. II. __________________________________________ |
B4 Deinococcus-Thermus
Deinococcus radiodurans Resistance to radiation Thermus aquaticus Production of Taq polymerase B5 Chrysiogenetes Single species Anaerobic respiration using arsenate |
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Domain Bacteria
III._______________________________________________ A. B. |
B10 Cyanobacteria
Oxygenic photosynthetic bacteria Once called blue-green algae (not algae) Major nitrogen fixer Carbon from CO2 Nitrogen as N2 Heterocysts Specialized cells for fixation of nitrogen Photosynthesis in other cells |
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Domain Bacteria
IV.________________________________________________ A. B. V. _________________________________________________ (largest phyla of bacteria; contains 5 major classes) |
B11 Chlorobi
Anoxygenic phototrophic bacteria Anaerobic environments Photosynthetic Found in deep, clear bodies of water B12 Proteobacteria Largest phylum 1300+ species Alphaproteobacteria class Betaproteobacteria class Gammaproteobacteria class Deltaproteobacteria class Epsilonproteobacteria class |
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Alphaproteobacteria
A.___________________________________ 1. 2. 3. 4. |
Environmentally important genera
Acetobacter Production of acetic acid in vinegar Agrobacterium Produce cancerlike disease of plants Ti plasmids Rhizobium and Bradyrhizobium Symbiotic nitrogen-fixing bacteria Root nodules of legumes Appendaged bacteria Prosthecate bacteria—found in aquatic environs |
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Betaproteobacteria
B.__________________________________________ 1. 2. 3. |
Bordetella
B. pertussis—causes whooping cough Neisseria N. meningitidis—meningitis N. gonorrhoeaea—gonorrhea Sheathed bacteria Tube surrounding bacteria Contaminated water and sewage treatment |
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Gammaproteobacteria
C.___________________________________________ 1. 2. 3. 4. |
13 orders
Enterobactgeriales Contain the enteric bacteria Include human pathogens Salmonella typhi Shigella spp. Yersinia pestis Escherichia coli Vibrionales Curved rods Vibrio chlerae--cholera Pasteurellales Pasteurella and Haemophilus genera Pseudomonales P. aeruginosa |
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Deltaproteobacteria
D.___________________________________________ 1. 2. |
Sulfur-reducing bacteria
Sulfates and sulfur to hydrogen sulfide Mud flats, brackish water Desulfovibrio spp. Black metal sulfides of Black Sea Gliding Fruiting bacteria Myxobacteria Soil organisms |
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Epsilonproteobacteria
E.____________________________________________ |
Campylobacter
C. jejuni—diarrheal illness Helicobacter H. pylori—gastric ulcers |
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Domain Bacteria
VI. ___________________________________ A. Three classes: 1. 2. 3. |
B13 Firmicutes
Three classes Clostridia Endospore forming Strict anaerobes Bacilli Endospore forming Aerobic and/or facultative anaerobes Mollicutes Lack cell wall Mycoplasmas Gram-positive cocci Spread between Clostridia and Bacilli classes |
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Domain Bacteria
B. Gram + cocci: 1. 2. 3. |
B13 Firmicutes (continued)
Gram-positive cocci Arrangement important for identification Physiological differences Staphylococcus Facultative anaerobes Four genera produce lactic acid Streptococcus spp. Leuconostoc Pediococcus Lactobacillus |
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Domain Bacteria
VII. ______________________________________ A. B. C. |
Actinobacteria
Oddly shaped bacteria Arthrobacter genus Change shape during growth Bifidobacterium genus Irregular branched cells Propionibacterium acne Corynebacterium diptheriae Acid-fast Mycobacterium Tuberculosis and Hansen’s disease Nocardia Spore-forming Actinomycetes Abundant in soil |
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Domain Bacteria
VIII._________________________________________________ A. B. C. |
B16 Chlamydiae
Obligate intracellular parasites Complicated reproductive cycle Reticulate body vegetative cell multiplication Elementary body Chlamydiospore Spread of infection |
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Domain Bacteria
IX._________________________________________________ A. B. C. D. X._________________________________________ A. B. C. |
B17 Spirochaetes
Helical shape Corkscrew motility Flagella—two axial filaments Metabolically diverse Causes of human disease Treponema pallidum—syphilus Leptospira interrogans—leptospirosis Borrelia burgdorferi—Lyme’s disease |
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Domain Bacteria
XI. ______________________________________ A. B. |
B20 Bacteroidetes
Purple nonsulfur bacteria Photosynthetic Bacteroides Mouth and intestinal tract B21 Fusobacteria Oral and respiratory systems F. periodonticum dental abscesses F. nucleatum Respiratory system |
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Fungi
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General characteristics
heterotrophic nonphototrophic absorptive saprophytic decompose to obtain nutrients some pathogens |
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Fungi
B. Morphology 1. Consists of interconnected branched filaments a. individual filaments are called _____________ (composed of chitin) b. mass of filaments is called a __________________ |
Morphology
interconnected branched filaments Hyphae individual filaments Mycelium connected hyphae coenocytic--undivided septa--incomplete divisions |
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Fungi
2. ______________= body of the fungus a. _______________=single cell (descriptive, not taxonomic) Most used industrially = ________________________ b. ________________- form open, wooly mycelium c. _________________-refers to the ability to express both forms d. ________________________-fruiting structure of a fungus (ex. Mushroom) |
Thallus
body of the fungus Yeasts single cells, oval shaped Molds mycelium Dimorphic stages of both yeast and mold Fleshy fungi fruiting structures mushrooms |
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Fungi
C. Reproduction 1. Asexual (no fusion of gametes) a. b. c. 2. Sexual – spores involve the fusion of gametes |
Reproduction
Classification based on reproduction Assexual elongation and fragmentation budding division of cells asexual spores sporangiospores conidiospores Sexual spores sexual fusion of gametes |
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Fungi
D. Lower Fungi ( all are ______________) Major classes include: 1._______________________________-water molds; flagellated gametes 2._______________________________-water molds; non-motile sexual spores 3. _______________________________ - terrestrial mold; diseases=zygomycoses |
Lower Fungi
Coenocytic Five classes Chytridiomycetes Water molds Gametes motility by flagella Oomycetes Water molds Nonmotile sexual spores Zygomycetes Terrestrial molds Disease: zygomycoses |
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Fungi
E. Higer Fungi (_____________ hyphae) Major classes include: 1. _________________________ - ascospores 2. _________________________ - basidiospores 3. _________________________ - no sexual spores |
Higher Fungi
septate hyphae Ascomycetes ascospores Basidiomycetes basidiospores mushrooms Deuteromycetes no sexual spores Penicillium |
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Fungi and Plants
F. Plant Diseases ( fungi are major cause) 1. ________________________ - two devastating genera a. _____________________ - attacks young plants b. ______________________-Ex. Irish potato blight 2. Some element of control by ___________________________________ |
Plant diseases
Lower fungi Pythium spp.--Damping off Phytophthora infestans--Potato tuber slime Phytophthora ramorum--Sudden oak death Higher fungi Many diseases Apple scab, corn smut, Dutch elm disease Control Anti-fungal sprays Fungus-resistant plants |
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Fungi and Humans
G. Human Associated Disease 1. referred to as _________________________ 2. not highly contagious, however difficulty in ___________________ H. Toxins 1. Muscarin- 2. A. phalloids- 3. Aspergillis- *note: some are beneficial such as ________________________ and ___________________________ |
Human disease
Mycoses Most often acquired from nature Treatment is difficult Toxins Muscarin Amanita muscaria mushroom Phalloidin and amanitin A. phalloides mushroom Ergot Claviceps purpurea—mold on rye Aflatoxin Aspergillus spp. Black mold toxin (sick building syndrome) Stachybotrys chartarum |
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Algae
II. Algae A. General Characteristics 1. photosynthetic – similar to chlorophyll found in _____________, able to generate ___________, and able to utilize __________ 2. range from microscopic singe cells to huge multi-cellular organisms 3. lack tissue differentiation 4. reproduce by unicellular asexual spores and gametes 5. mostly motile by ___________________ B. Ecology 1. mainly found in _______________ environments 2. __________________ - can live inside other organisms 3. commercially responsible for the production of _____________________ (thickener), ________________, and ______________________ |
Aquatic
freshwater marine Terrestrial moist soil tree bark surface of rocks Endophytic live in other organisms Varied environments Commercial Carageenan thickener Agar Alginic acid thickener Food protein supplement animal food |
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Algae
C. Six groups are recognized according to their form ,structure of walls, and pigments they produce. 1. ____________________________ - euglenoids 2. ____________________________ - dinoflagellates 3. _____________________________-diatoms 4. _____________________________-green algae 5. _____________________________- red algae 6. _____________________________-brown algae |
Classification
Six groups form of thalli wall structure pigments Euglenoids Dinoflagellates Diatoms Green algae Brown algae Red algae |
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Lichens
III. Lichens (not organisms!) 1. composed of a ___________________ (dominant organism) and a(n) _____________________. 2. ___________________________ relationship |
Mutualistic association
fungus phototroph algae cyanobacteria |
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Protozoa
IV. Protozoa A. General Characteristics 1. 2. 3. B. Four groups based n motility 1. flagellates: _________________________ 2. amoeba:____________________________ 3. non-motile, all parasitic: _____________________________________ 4. ciliates: _______________________________ |
Four groups
based on motility Flagellate Mastigophora Amoeboid Sarcodina pseudopods Sporozoa nonmotile Ciliate cilia |
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Slime molds
C. Slime Molds Two groups: 1. 2. RNA containing viruses assemble in the |
Not fungi
Two groups True slime molds Slimy, veined mass Multinucleated cytoplasm Cellular slime molds Cells resemble amoeboid protozoa Dictyostelium discoideum Morphological changes in life cycle |
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Relatedness of Eukaryotes
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Figure 12.19
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Helminths
V. Helminths A. Flatworms (AKA: __________________________________) 1. 2. 3. B. Roundworms (AKA:________________________________) |
Flatworms
tapeworms scolex attachment hooks/sucker germinal center new segments proglottids segments flukes Roundworms nematodes |
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Life Cycle of Beef Tapeworm
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Figure 12.21
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Arthropod Vectors
B. Roundworms (AKA:________________________________) VI. Arthopod Vectors 1. A vector is an organism that _________________________________________________________________. 2. Provide a reservoir of _______________________________ 3. ____________________________- refers to an infective organism (ex. Mites) |
Reservoir of infection
mechanical vector external transmission not essential link biological vector part of life cycle internal transmission |
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Arthropod Vectors
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Reservoir of infection
mechanical vector external transmission not essential link biological vector part of life cycle internal transmission |
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What is a virus?
The entire acellular viral particle is called a |
= obligate, intracellular parasites that contain either
DNA or RNA; depend on synthetic machinery of host cell for replication of the infectious particle called the virion |
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General characteristics viruses
The largest vertebrate viruses are the |
Size - submicroscopic; most are beyond limit of resolution of light
microscope (exception = poxviruses; can be seen under light microscope with proper illumination); size varies from 25 m to 250 m (approximately 0.1 diameter of E. coli cell) |
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Structural components
The type of nucleic acid found in viruses is Viruses enter the host cell via both viropexis AND membrane fusion The protective protein which surrounds the viral nucleic is called a |
a. Nucleic acid core = genome - may be either DNA or RNA
but never both; may be either single stranded (ss) or double stranded (ds); used in classification (ssDNA, ssRNA, dsDNA, or dsRNA); may be either linear or circular; found in all mature virus particles (virions) b. Protein coat = capsid - shell surrounding and protecting nucleic acid core; composed of identical subunits called capsomeres; subunits undergo self-assembly into geometric shapes around nucleic acid core; number of capsomeres is unique for each virus; contain receptors that combine with complementary sites on host cell surface for attachment; found in all mature viruses c. Envelope - lipid and protein membrane surrounding virion; origin = host cell membrane; lipid of envelope make viruses susceptible to lipid solvents and are more heat labile than non-enveloped viruses; found only in viruses that exit cell through cell membrane or bud through nuclear mem- brane during maturation; viruses without envelope are called naked d. Glycoprotein spikes - surface projections coded for by viruses; manufactured in host cell and become incorporated into host cell membrane prior to virion maturation; often act as receptors for host cells; may agglutinate rbc's particles (virions) |
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Shape
The largest vertebrate viruses are the |
a. Protein shell may assume either icosahedral (20 equilateral
triangular faces = cubic symmetry) or helical (rod-shaped particles composed of repeating protein subunits surround- ing core in a helical fashion = helical symmetry) shape; some viruses (e.g. poxviruses) have a complex shape |
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Classification of Viruses
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A. Criteria for classification
1. Nature of disease (e.g. neurotropic viruses) 2. Organ system most frequently involved (e.g. hepatitis viruses) 3. Physiochemical characteristics a. Type of nucleic acid (ssDNA, ssRNA, dsDNA, dsRNA) b. Presence or absence of envelope - ether sensitive are enveloped while ether resistant = naked 4. Size (small = picornaviruses to large = poxviruses) B. Vertebrate viruses classified into 13 families of RNA-containing viruses and 7 families of DNA viruses |
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III. Replication Cycle
DNA viruses undergo maturation in the hosts |
A. Attachment & adsorption - cell surface phenomenon; adsorption involves
specific interaction between sites on viruses and receptors on cell mem- brane of host cell via ionic or electrostatic interactions (e.g. HIV attaches via gp120 of virus to CD4 receptor on T cells); tropism = susceptibility of only certain cells to particular viral agent - may be related to presence or absence of receptors on host cell B. Penetration - usually occurs by fusion (enveloped viruses) or phagocytosis (naked viruses) C. Uncoating - involves removal of protein coat and release of viral nucleic acid; may involve host enzymes (proteolytic) and/or viral coded enzymes brought in with virus or synthesized in new host D. Biosynthesis 1. Involves synthesis of viral nucleic acid, viral coat proteins and virus-specific enzymes - each is synthesized separately 2. Site of viral synthesis varies depending on type of NA; general- izations include: a. Most DNA viruses synthesize DNA in nucleus of host cell & proteins (structural & enzymatic) in cytoplasm b. Most RNA viruses synthesize all viral components in cyto- plasm 3. No infectious virus particles are detected during this period = eclipse period E. Maturation (Assembly of virions) - involves combining of synthesized NA and protein; occurs in nucleus with most DNA viruses & cytoplasm with most RNA viruses; most capsids self-assemble around genome; defective (incomplete) viruses occur when NA is not coated by protein (empty coats or non-viral NA placed in coat) F. Release 1. Host cell disintegration (lysis) - occurs when cell fills with virus particles; causes death of cell and release of naked viruses 2. Slow release through cell membrane as part of budding process - results in release of enveloped viruses; cell may not die for a long time & can continue to shed virus particles; some proteins synthe- sized under viral control become incorporated into CM of host and become incorporated into virion as virus buds through membrane (glycoprotein spikes); important in cellular immunity (proteins are antigenic and host recognizes these proteins as foreign mounting immune response against cells with these proteins in their mem- branes) |
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IV. Effects of Viruses on Host Cells & Host Cell Responses
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A. Effects of viruses on host cells = cytopathic effects (CPE) - morphologic
alterations that occur in virus-infected cells; often visible in light micro- scope 1. Inclusions = intracellular structures; may be cytoplasmic or nuclear; represent aggregates of viral nucleic acid or protein, mature virions or degenerative cell reaction products; serve as markers of certain viral infections (e.g. Negri bodies = intracytoplasmic inclusions of rabies infection; Owl's eyes = cytomegaloviruses) 2. Syncytia (multinucleated giant cells) - represent fusion of virus- infected cells with contiguous uninfected cells; form giant cells with many nuclei; caused by virus-induced changes in CM; allows cell to cell spread of virus without coming in contact with humoral immunity (e.g. respiratory syncytial viruses) 3. Cell necrosis or death - rate of destruction depends on degree of shut-down of host cellular functions and rate of synthesis with accumulation of toxic viral structural proteins; cytolytic effects are visible microscopically and when destruction is extensive, effects can be seen with naked eye forming areas referred to as plaques in tissue cultures; in vivo, destruction of large numbers of cells results in impairment of tissue or organ structure & function B. Host response 1. Non-immunological = interferon production 2. Immunological a. Humoral - inhibits adsorption of virus to host cell surface (blocks receptors on virus) b. Cell mediated - acts against viral-specific proteins incor- porated into host cell membrane; involves destruction of infected cell by sensitized T cells |
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V. Laboratory Techniques with Viruses
Cell cultures which can be subcultured indefinitely are called |
A. Viral isolation - require present of living cells
1. Laboratory animals - suckling animals usually more susceptible than adult animals (e.g. suckling mice or guinea pigs) 2. Embryonated eggs - chick or duck eggs used most often; viruses grow in embryo or on membranes 3. Tissue culture a. Primary cell lines - prepared directly from tissue excised from humans or animals (e.g. primary monkey kidney = PMK cells) b. Continuous cell lines - cells that have been passaged indef- initely; are usually derived from malignant or premalignant cells (e.g. HeLa from human cervical carcinoma and HEp-2 from human laryngeal carcinoma |
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B. Serological methods
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1. Patient's serum - show rising titer of antibodies to specific viruses
2. Tissue culture - used to identify viruses that have been grown in the laboratory; have specific antisera for viruses; most often show neutralization of effect by antisera as indication of identity of virus |
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VI. Chemotherapy
Most RNA viruses obtain their envelope from the |
A. Amantadine - synthetic amine; prevents penetration & uncoating of virion;
antiviral activity limited to influenza A virus; effective when administered shortly before (prevent spread in epidemics) or shortly after contact with virus B. Vidarabine(Ara-A) - synthetic purine nucleoside; inhibits viral DNA polymerases and cellular DNA & RNA polymerases; used primarily in treatment of herpes simplex encephalitis, neonatal herpes simplex and severe varicella and zoster infections in immunocompromised C. Acyclovir - acts by inhibiting DNA polymerase; used to treat herpes- virus infections; decreases symptoms - does not cure D. Azidothymidine (AZT) - inhibits RNA and DNA polymerases & some viral enzymes; used primarily in treatments of AIDS |
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VII. DNA viruses of interest
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A. Herpesviruses
1. Characteristics a. Relatively large viruses; dsDNA, linear core and icosa- hedral capsid; enveloped b. Replicate & assembles in nucleus - bud through nuclear & cytoplasmic membranes during maturation & release c. Require direct transmission - fragile; susceptible to drying & inactivation by heat, mild detergents & lipid solvents d. Virions spread from cell to cell at points of contiguous cell contact leading to local spread of lesions - infections at distant sites rare e. Typically cause latent infections (recur for years) 2. Clinical manifestations a. Herpes simplex - type 1 & 2 i. Keratoconjunctivitis - inflammation & swelling of tissues of anterior eye; potential vision loss ii. Cold sores (usually type 1) iii. Genital lesions (usually type 2) iv. CNS - meningoencephalitis & encephalitis v. Typically cause latent infections (recur for years) b. Varicella-Zoster i. Varicella = chickenpox; primary disease; usually epidemic; usually mild & self-limiting ii. Zoster = shingles reactivation of latent varicella virus; usually seen in later life; mechanism of activation unknown; often associated with stress c. Cytomegalovirus i. Congenital (in utero) or neonatal disease most common manifestation; may lead to mental retarda- tion ii. Infections of immunocompromised also seen; often disseminated; individuals most likely = transplants & individuals with AIDS d. Epstein-Barr = infectious mononucleosis (acute, self- limiting) & Burkitts lymphoma 3. Latency a. Process not completely understood; appears not all viral genes are expressed at all times leading to lack of viral DNA and mature virion synthesis b. Not known whether viral DNA integrated into chromosome or remains a separate plasmid-like element c. Viruses perist for life in nerve cells (herpes simplex & Varicella-Zoster), in neutrophils & monocytes (VZ) & in lymphocytes & salivary glands (CMV) d. Reactivation produces symptoms - may be triggered by sunburn, systemic infections, immune impairment, emotional stress & menstruation 4. Prevention & Control a. Avoid sexual contact during active genital infections b. Administration of specific human immune globulin promptly after exposure - used to prevent chickenpox in immunodeficient children c. Administration of live attenuated vaccine (chickenpox) d. Treatment = acyclovir; decreases duration & severity of disease - no cure |
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B. Hepatitis viruses
The complete virion of the hepatitis B virus is called a Hepatitis B infection can be prevented by Viruses attach to a surface component on the host cell called a(n) |
1. Viral agents
a. Hepatitis A (HAV) = ssRNA (picornaviruses or enterovirus) b. Hepatitis B (HBV) = dsDNA (hepadnavirus) c. Hepatitis C (HCV) = ssDNA (thought to be related to flavi- viruses) d. Hepatitis D (HDV) = ssRNA ( viroid = naked viruses that lack coat protein) surrounded by hepatitis B surface antigen (delta agent) - defective HBV; infective only in presence of HBV infection e. Hepatitis E (HEV) = ssRNA (not presently classified) 2. Clinical manifestations - Epidemiology a. HAV - can be asymptomatic or symptomatic with or with- out jaundice; symptoms include GI (anorexia, vomiting & pain in area of liver); does not become chronic nor result in carrier state; relapses may occur; transmitted by fecal-oral route (has been associated with food - most commonly uncooked oysters harvested from feces-contaminated waters); hygiene most important control measure; close contacts may be given immune globulin; vaccine may be available in a few years b. HBV - 3 morphological forms found in infected individuals = Dane particle (mature virion) + spherical & filamentous forms (incomplete viruses; not infectious); clinically can be asymptomatic to symptomatic with or without jaundice or fulminant (hepatic encephalopathy occurs during acute phase; eventually coma & death can occur; can become chronic but most completely recover; been associated with primary hepatocellular carcinoma; transmitted by parenteral routes (tattooing, acupuncuture, ear piercing, shaving, manicuring, drug abuse, transfused blood, etc) and by close contact with contaminated secretions (saliva, urine, tears, CSF & semen - not feces); control involves screening of blood donors, sterilization of medical & dental instruments, vaccine (Recombivax = yeast containing cloned viral genes) for health care workers; treatment of chronic HBV presently uses interferon- (induces remission in 25-50% of cases); passive immunization following exposure uses hepatitis B immune serum globulin (HBIG) c. HCV - milder than HBV infection; persistent & chronic infection common; cirrhosis may develop; may be asso- ciated with primary hepatocellular carcinoma; most cases are transfusion-associated but may follow non-parenteral exposure d. HDV (Delta antigen-associated hepatitis) - follows coin- fection of liver with HBV or superinfection; associated with progressive liver disease resulting in death, especially in superinfections; transmission, control & treatment same as HBV e. HEV - symptoms similar to HAV; seen in waterborne epidemics in developing countries |
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VIII. RNA Viruses of Interest
Retroviruses utilize the enzyme ________ to make a DNA copy of their RNA. |
VIII. RNA Viruses of Interest
A. Retroviruses (possess a reverse transcriptase - allows virus to make a dsDNA intermediate which can integrate into host genome) 1. Viral agents a. Human Immunodeficiency Virus I & II (HIV) b. Human T-cell lymphotropic retrovirus I & II (HTLV) 2. HIV a. ssRNA, enveloped virus b. Preferentially infects T helper cells (lymphocytes that express the CD4 surface antigen = receptor for gp120 surface antigen of HIV) c. Antigenic variability associated with variability in genome, particularly segments associated with enveloped genes d. Key indicator diseases = Kaposi sarcoma, P. carinii pneumonia, cryptosporidiosis or isosporiasis with diarrhea of more than 1 month, mucocutaneous herpes simplex ulcers, CMV disease of more than 1 month, mycobacterial infections (esp. MAC complex) B. Picornaviruses 1. ssRNA - naked 2. Contain 2 groups of viruses a. Enteroviruses (intestinal) = polioviruses, Coxsachie & ECHO; may cause CNS infection (aseptic meningitis & encephalitis) b. Rhinoviruses (respiratory) = common cold; over 100 different strains recognized 3. Polioviruses (types A, B & C) prevented by vaccine a. Salk = killed virus (injection) b. Sabin = live attenuated virus (oral) C. Orthomyxoviruses (Influenza viruses) 1. ssRNA - segmented genome and enveloped 2. Important antigens a. Nucleoprotein - divides viruses into 3 types recognized = A, B, and C b. Hemagglutinin (H) - glycoprotein spike on surface of virion; determines subtypes; attaches to neuraminic acid- containing glycoproteins on surfaces of host cells; initiates infection (receptor) and causes agglutination of rbc’s; anti- body to this antigen prevents infection c. Neuraminidase (N) - glycoprotein spikes on types A & B but not C; determines subtypes; breaks bond between H spike and cell surface; antibody not protective d. Major changes in amino acid sequence of glycoprotein spikes resulting in changes in subtypes occur at intervals = antigenic shift; minor changes in amino acid sequence of glycoprotein spikes resulting in decreased affinity of virus for antibody to original spikes but no change in subtypes occur during epidemics = antigenic drift e. Influenza A undergoes both shift & drift; influenza B undergoes drif but not shift; influenza C seems to be anti- genically stable f. Antigenic shift in virus often results in pandemics 3. Clinical manifestations (influenza A) a. Acquired by inhalation; often asymptomatic; symptoms include fever, chills, myalgia, sore throat & dry cough b. Recovery occurs in several days; convalescents may take weeks c. Mortality low but number of cases usually high so numbers of deaths can be significant d. Death result of primary influenza pneumonia or secondary bacterial pneumonia caused most often by Streptococcus pneumoniae, Staphylococcus aureus or Haemophilus influenzae e. Elderly & persons with chronic diseases at high risk 4. Control & treatment a. Vaccination of high-risk persons (formalin-inactivated virus grown in eggs) best control; must be made new each year to contain strain present in outbreaks for that year b. Treatment = amantadine or rimantadine; reduce duration of illness & virus shedding |
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D. Togaviruses (rubella)
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1. ssRNA - enveloped
2. Produces mild disease in young children & adults - may be inapparent or rash, low-grade fever & lymphadenopathy occur; arthritis and arthralgia may occur in adults; complications rare 3. Infection in early pregnancy can be disastrous a. The earlier in pregnancy the infection; the more severe the damage; infection after 4th month usually not severe b. Abnormalities include cataracts, glaucoma, deafness, congenital heart disease & mental retardation 4. Transmitted by direct contact with infected respiratory secretions 5. Vaccine method of control = live attenuated vaccine; provides long-lasting immunity; vaccine virus can infect fetus (vaccine should not be given 3 months before conception or during preg- nancy |
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Chapter 12
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The kingdom Protista includes these two groups of microorganisms.
a. algae and bacteria b. fungi and protozoa c. algae and protozoa d. algae and fungi status: incorrect (0.0) correct: c your answer: d feedback: Incorrect. -------------------------------------------------------------------------------- 2 Fungi a. have a cell wall, require oxygen, absorb nutrients b. are non-motile, multicellular, reproduce via spores c. neither are non-motile, multicellular, reproduce via spores NOR have a cell wall, require oxygen, absorb nutrients d. both are non-motile, multicellular, reproduce via spores AND have a cell wall, require oxygen, absorb nutrients status: not answered () correct: d your answer: -------------------------------------------------------------------------------- 3 Fungi have a cell wall made of a. peptidoglycan b. pectin c. chitin d. cellulose status: not answered () correct: c your answer: -------------------------------------------------------------------------------- 4 The major types of photopigments in plant-like protists include a. all of these choices b. carotinoids c. chlorophyll a d. chlorophyll b status: not answered () correct: a your answer: -------------------------------------------------------------------------------- 5 Plant-like protists accumulate starch reserves in regions of the chloroplast known as a. macro-nuclei b. pyrenoids c. protoplasts d. starch vacuoles status: not answered () correct: b your answer: -------------------------------------------------------------------------------- 6 Asexual reproduction in the plant-like protists may be accomplished by a. all of these choices b. spore production c. fission d. fragmentation status: not answered () correct: a your answer: -------------------------------------------------------------------------------- 7 Red tides are due to blooms of a. all of these choices b. diatoms c. dinoflagellates d. brown algae status: not answered () correct: c your answer: -------------------------------------------------------------------------------- 8 The plant-like protists all possess the photopigment a. chlorophyll c b. chlorophyll d c. chlorophyll a d. chlorophyll b status: not answered () correct: c your answer: -------------------------------------------------------------------------------- 9 The ________ algae are primarily marine algae. a. brown and red b. green and gold c. red and golden d. green and red status: not answered () correct: a your answer: -------------------------------------------------------------------------------- 10 Agar is a derivative of ________ algae. a. brown b. green c. golden d. red status: not answered () correct: d your answer: -------------------------------------------------------------------------------- 11 A unicellular plant-like protist which lacks a cell wall is called a. diatom b. euglena c. dinoflagellate d. kelp status: not answered () correct: b your answer: -------------------------------------------------------------------------------- 12 During the protozoan life cycle the actively feeding and reproducing form of the organism is called a a. cyst b. trophozoite c. spore d. none of these choices status: not answered () correct: b your answer: -------------------------------------------------------------------------------- 13 The structure of an animal-like protist required for sexual reproduction a. none of these choices b. micronucleus c. macronucleus d. pellicle status: not answered () correct: b your answer: -------------------------------------------------------------------------------- 14 A cavity in an animal-like protist, which directs food to a specific site a. pellicle b. none of these choices c. cytostome d. contractile vacule status: not answered () correct: c your answer: -------------------------------------------------------------------------------- 15 Group of animal-like protists, which are nonmotile or motile by means of gliding locomotion. a. sporozoans b. flagellates c. amoebas d. ciliates status: not answered () correct: a your answer: -------------------------------------------------------------------------------- 16 Group of animal-like protists motile by means of flagella. a. sporozoans b. flagellates c. amoebas d. ciliates status: not answered () correct: b your answer: -------------------------------------------------------------------------------- 17 Group of animal-like protists motile by cytoplasmic streaming and formation of pseudopods. a. flagellates b. amoebas c. sporozoans d. ciliates status: not answered () correct: b your answer: -------------------------------------------------------------------------------- 18 Group of animal-like protists motile by means of cilia. a. amoebas b. ciliates c. sporozoans d. flagellates status: not answered () correct: b your answer: -------------------------------------------------------------------------------- 19 Dart-like weapons on the surface of some ciliates. a. trichocysts b. trophozoites c. none of these choices d. cysts status: not answered () correct: a your answer: -------------------------------------------------------------------------------- 20 Life cycle form of Plasmodium released from liver cells during infection. a. sporozoite b. schizont c. merozoite d. trophozoite status: not answered () correct: c your answer: -------------------------------------------------------------------------------- 21 Filamentous mass of fungi. a. hyphae b. all of these choices c. spores d. mycelia status: not answered () correct: d your answer: -------------------------------------------------------------------------------- 22 Fungi that alternate between a mycelial form and a yeast form. a. septate b. yeast c. dimorphic d. none of these choices status: not answered () correct: c your answer: -------------------------------------------------------------------------------- 23 Microbes which undergo sexual reproduction. a. fungi b. amoeba c. all of these choices d. algae status: not answered () correct: c your answer: -------------------------------------------------------------------------------- 24 Sexual fungal spore contained within a sac. a. zygospores b. basidiospores c. none of these choices d. ascospores status: not answered () correct: d your answer: -------------------------------------------------------------------------------- 25 A lichen may have as one of its components. a. algae b. fungi c. cyanobacterium d. all of these choices |
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Chapter 13
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Web Quiz
Assignment Name: Batzing, Microbiology: An Introduction, 1/E, Ch 13 Summary of Results Total Possible: 23.0Time Spent: 13432d 03:04:48 incorrect 1.00 4.35% not answered 22.0 95.65% To email the results to your instructor(s), complete this form: E-mail results to: Additional message: Your first name: Your last name: Your email address: Required field -------------------------------------------------------------------------------- 1 The type of nucleic acid found in viruses is a. DNA b. neither DNA NOR RNA c. both DNA AND RNA d. RNA status: incorrect (0.0) correct: c your answer: b feedback: Incorrect. -------------------------------------------------------------------------------- 2 The protective protein which surrounds the viral nucleic is called a a. nucleocapsid b. capsid c. capsomere d. envelope status: not answered () correct: b your answer: -------------------------------------------------------------------------------- 3 Protein projections that cover the envelope surface and enable viruses to attach to host cells are called a. capsomeres b. spikes c. virions d. capsids status: not answered () correct: b your answer: -------------------------------------------------------------------------------- 4 The entire acellular viral particle is called a a. capsomere b. viroid c. capsid d. virion status: not answered () correct: d your answer: -------------------------------------------------------------------------------- 5 Viral nucleic acid and the protein capsid that surround the nucleic acid makes up the a. capsid b. capsomers c. viroid d. nucleocapsid status: not answered () correct: d your answer: -------------------------------------------------------------------------------- 6 Viruses that infect bacteria are called a. phages b. flaviviruses c. bacterioviruses d. arboviruses status: not answered () correct: a your answer: -------------------------------------------------------------------------------- 7 The largest vertebrate viruses are the a. togaviruses b. rhabdoviruses c. filoviruses d. poxviruses status: not answered () correct: d your answer: -------------------------------------------------------------------------------- 8 The complete virion of the hepatitis B virus is called a a. Dane particle b. capsid c. deltavirus d. poxviruse, status: not answered () correct: a your answer: -------------------------------------------------------------------------------- 9 Hepatitis B infection can be prevented by a. use of a latex condom b. sexual abstinence c. vaccines d. all of these choices status: not answered () correct: d your answer: -------------------------------------------------------------------------------- 10 A viral disease, which has been eradicated. a. influenza b. measles c. Smallpox d. polio status: not answered () correct: c your answer: -------------------------------------------------------------------------------- 11 Group of viruses usually transmitted by mosquitoes a. retroviruses b. rhabdoviruses c. flaviviruses d. herpesviruses status: not answered () correct: c your answer: -------------------------------------------------------------------------------- 12 Most RNA viruses obtain their envelope from the a. cytoplasmic membrane b. endoplasmic reticulum c. Golgi membrane complex d. nuclear membrane status: not answered () correct: a your answer: -------------------------------------------------------------------------------- 13 Retroviruses utilize the enzyme ________ to make a DNA copy of their RNA. a. reverse transcriptase b. ligase c. primase d. DNA polymerase status: not answered () correct: a your answer: -------------------------------------------------------------------------------- 14 DNA viruses undergo maturation in the hosts a. neither nucleus NOR cytoplasm b. both nucleus AND cytoplasm c. nucleus d. cytoplasm status: not answered () correct: c your answer: -------------------------------------------------------------------------------- 15 Cellular transformation of host cells may be brought about by a. proviral integration b. both proviral integration AND expression of proviral genes c. expression of proviral genes d. neither proviral integration NOR expression of proviral genes status: not answered () correct: b your answer: -------------------------------------------------------------------------------- 16 The smallest known pathogens that cause plant disease a. satellites b. viroids c. prions d. deltavirus status: not answered () correct: c your answer: -------------------------------------------------------------------------------- 17 Infectious proteins a. prions b. deltavirus c. viroids d. satellites status: not answered () correct: c your answer: -------------------------------------------------------------------------------- 18 Viruses attach to a surface component on the host cell called a(n) a. receptor b. phage c. spike d. capsid status: not answered () correct: c your answer: -------------------------------------------------------------------------------- 19 Cell cultures which can be subcultured indefinitely are called a. none of these choices b. cell lines c. primary cultures d. standard cultures status: not answered () correct: c your answer: -------------------------------------------------------------------------------- 20 Viruses which exist as unintegrated plasmids-like nucleic acid. a. none of these choices b. virion c. provirus d. episome status: not answered () correct: a your answer: -------------------------------------------------------------------------------- 21 Morphological forms of nucleocapsids include a. complex b. helical c. all of these choices d. cubic status: not answered () correct: c your answer: -------------------------------------------------------------------------------- 22 RNA containing viruses assemble in the a. nucleus b. neither cytoplasm NOR nucleus c. both cytoplasm AND nucleus d. cytoplasm status: not answered () correct: d your answer: -------------------------------------------------------------------------------- 23 Viruses enter the host cell via a. viropexis b. both viropexis AND membrane fusion c. membrane fusion d. neither viropexis NOR membrane fusion status: not answered () correct: b your answer: |
