test 5 – Microbiology – Flashcards
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| What are the gram negative spirochetes |
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Treponema pallidum Borrelia burgdorferi |
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| What are the gram negative spirillum? Are the urease positive or negative? |
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| Helicobacter pylori (urease positive) Campylobacter jejuni (urease negative) |
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| What is the gram negative vibrio? What are some characteristics of it? |
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| Vibrio cholera lactose negative oxidase and glucose positive |
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| What are the gram negative aerobic cocci? |
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| Neisseria gonorrhoeae Neisseria meningitides Moraxella catarrhalis |
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| What are the gran negative aerobic rods (coccobacilli)? |
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| Bordetella pertussis Legionella pneumophila Haemophilus influenza Brucella abortus |
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| What are the gram negative aerobic rods (bacilli) |
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| Pseudomonas aeruginosa Rhizobium leguminosarum |
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| What are the fast fermenting gram negative enterics |
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| Klebsiella Escherichia Enterobacter |
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| What are the slow fermenting gram negative enterics |
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| Serratia Citrobacter |
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| What are the non-coliform enteric pathogens (gram negative enterics) |
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| Proteus mirabilis Yersinia entercolitica Yersinia pestis |
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| What gram negative species cause gastrointestinal problems |
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| Helicobacter pylori Salmonella enteritidis Salmonella typhi |
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| What gram negative species cause dental caries? |
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| Streptococcus mutans, S. mitis, S. oralis, S. sanguis, S. gordonii, Lactobacillus acidophilus |
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| What gram negative species cause gingivitis |
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| Streptococcus mutans, Fusobacterium and Actinobacteria (anaerobes) |
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| What microbes cause periodontal disease |
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| Campylobacter jejuni, Treponema denticola, Porphyromonas gingivalis |
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| What microbes cause gastric and duodenal ulcers |
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| Helicobacter pylori |
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| What microbes cause gastroenteritis |
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| Salmonella, campylobacter, e. coli |
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| What microbe causes dysentery |
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| shigella |
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| What microbe causes antibiotic associated diarrhea and pseudomembranous colitis |
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| Clostridium difficile |
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| What microbe causes Asiatic cholera |
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| vibrio cholerae |
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| What microbes cause food poisoning |
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| +Staphylococcus aureus +Bacillus cereus +Clostridium perfringens +Clostridium botulinum Campylobacter jejuni Salmonella typhimurium Escherichia coli O157:H7 |
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| What are some common bacterial foodborne pathogens |
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| Gram Positives: Bacillus cereus Listeria monocytogenes Staphylococcus aureus Streptococcus Vibrio parahaemolyticus Vibrio vulnificus Gram negatives: Escherichia coli Shigella spp. Vibrio cholera Yersinia enterocolitica |
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| What microbes cause food infections |
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| Salmonella E. Coli O157:7 Campylobacter jejuni +Listeria monocytogenes: Listeriosis |
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| What microbes cause general respiratory problems |
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| Hemophilus influenza Klebsiella pneumonia Legionella pneumophila Pseudomonas aeruginosa |
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| What microbes cause sinusitis |
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| Haemophilus influenza Pseudomonas aeruginosa |
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| What microbe causes strep throat |
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| + Streptococcus pyogenes |
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| What microbe causes diphtheria |
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| + Corynebacterium diphtheriae |
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| What microbes cause pneumonia |
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| Gram positives: Streptococcus pneumonia Staphylococcus aureus Streptococcus agalactiae Mycoplasma pneumonia (atypical) Moraxella catarrhalis Gram negatives: E. Coli Pseudomonas aeruginosa Haemophilus influenza Chlamydophila pneumonia (atypical) Legionella pneumonphila (atypical) Klebsiella pneumonia |
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| What microbe causes whooping cough |
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| - Bordetella pertussis |
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| What microbe causes tuberculosis |
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| + Mycobacterium tuberculosis |
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| What microbe causes chlamydia |
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| Chlamydia trachomatis |
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| What microbe causes gonorrhea |
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| Neisseria gonorrhoeae |
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| What microbe causes syphilis |
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| Treponema pallidum |
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| What microbes cause UTI's |
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| Escherichia coli Proteus mirabilis Enterobacter cloacae Serratia marcescens Pseudomonas aeruginosa Klebsiella pneumonia (2nd most common) +Staphylococcus aureus |
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| What microbes causes meningitis |
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| Neisseria meningitides Haemophilus influenza Streptococcus pneumonia Escherichia coli Listeria monocytogenes |
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| What microbe causes otitis externa |
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| - Pseudomonas aeruginosa |
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| What microbe causes otitis media |
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| +Streptococcus pneumonia -Haemophilus influenzae |
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| What microbe causes acne, boils, pimples, impetigo |
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| + Staphylococcus aureus |
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| What microbe causes hot tub itch, folliculitis, cellulitis |
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| - Pseudomonas aeruginosa |
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| What microbes cause necrotizing fasciitis |
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| Gram positives: Streptococcus pyogenes Staphylococcus aureus Vibrio vulnificus Clostridium perfringenes Bacteroides fragilis |
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| What microbe causes anthrax (zoonoses) |
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| + bacillus anthracis |
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| What microbe causes Brucellosis (zoonoses) |
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| - Brucella abortus |
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| What microbe causes Leptospirosis (zoonoses) |
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| Leptospira |
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| What microbe causes Lyme disease (arthropod borne) |
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| - Borrelia burgdorferi |
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| What microbe causes Ehrlichiosis (arthropod borne) |
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| +Ehrlichia |
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| What microbe causes Rickettsiosis (Typhus, Rocky mountain spotted fever) -- arthropod borne |
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| - Rickettsias |
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| What microbe causes plague? |
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| - Yersinia pestis |
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| What microbe causes toxic shock syndrome and scaled skin syndrome |
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| + staphylococcus aureus |
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| What microbe causes scarlet fever |
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| + streptococcus pyogenes |
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| What microbe causes Hemolytic Uremic Syndrome (HUS)? |
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| - E. Coli O157:H7 |
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| What microbe causes diptheria |
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| + cornebacterium diphtheriae |
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| What microbes cause nosocomial infections |
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| Gram positives: MRSA, Clostridium difficile Gram negatives: Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, Legionella pneumophila |
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| what are two groups of unrelated bacteria that are obligate intracellular parasites of eukaryotic cells? |
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| Rickettsias and chlamydiae |
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| What microbes can be described as energy parasites, and why? |
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| Chlamydiae are unable to produce enough ATP to sustain metabolism outside of a host cell |
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| What nosocomial infections can Acinetobacter baumanni cause? |
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| bacteremia, secondary meningitis, and ventilator-associated pneumonia in ICU |
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| What are the aerobic gram-negative nonenteric bacilli (do not ferment sugars)? |
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| pseudomonas, pseudomonas aeruginosa, brucella abortis, brucella suis, francisella tularensis, bordetella pertussis, legionella |
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| Where can you find the pseudomonas |
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| free-living, soil, seawater, freshwater, plants, animals |
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| Describe the characteristics of the pseudomonas |
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| small, gram-negative, single polar flagellum, oxidative, metabolically versatile (protease, amylase, pectinase, cellulase) |
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| What is most at risk for infections by pseudomonas aeruginosa |
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| burn patients and people with cystic fibrosis |
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| What infections does -pseudomonas aeruginosa cause? |
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| pneumonia, UTI, abscess, ear and eye infections, septicemia, endocarditis, meningitis, bronchopneumonia, corneal infectiosn with contacts, skin rashes |
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| What type of pathogen is -pseudomonas aeruginosa and what is it resistant to? |
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| opportunistic pathogen to the debilitated or immunocompromised. Resists soaps, dyes, quats, drugs, drying and heat. Chronic nosocomial pathogen. |
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| What zoonosis does -Brucella cause? How do they affect animals and humans? |
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| Brucella abortis (cows) Brucella suis (pigs) Brucellosis = Malta fever, undulant fever, Bang's disease. In animals, it crosses the placenta and causes abortion In humans, causes fever, chills, sweating, headache, muscle pain, weakness, weight loss, focal infections in the liver, spleen, bone marrow and kidneys. |
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| What does -Francisella tularensis cause? |
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| Tularensis- Rabbit fever- vectors include rabbits, rodents, wild animals, arthropods. Causes headache, backache, fever, chills, weakness, pharyngitis, conjunctivitis, swollen glands. |
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| What are the virulence factors of -Bordetella pertussis |
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| Whooping cough Receptors bind to ciliated epithelium. Toxins kill cells, build up mucus and block airways. |
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| What are the two stages of whooping cough |
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| -Bordetella pertussis 1. catarrhal stage: cold-like 2. paroxysmal stage: coughing fits, "whooping" |
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| What does -Legionella cause |
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| Legionnaire's disease: rising fever, cough, diarrhea, abdominal pain, lung consolidation, impaired respiration, impaired function |
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| Describe the characteristics of Legionella pneumophila |
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| gram-negative motile short rods, filaments, fastidious. Found in fresh water, aerosols, nosocomial |
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| Describe the Enterobacteriacae |
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| Gram-negative, small non-spore forming rods, aerobic, ferment when no O2, facultative anaerobes. Found in soil, water, decaying matter, large bowel. Ferment glucose, nitrates to nitrites, oxidase negative, catalase positive, often motile |
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| What is the difference between the coliforms and noncoliforms of the enterobacteriacae? |
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| coliforms ferment lactose quickly and noncoliforms are non or slow lactose fermenters |
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| What are some virulence factors of the enterobacteriacae? |
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| endotoxins overcome the host defenses quickly and multiply. Also enterotoxins, capsules, hemolysins, fimbrae to colonize the host. |
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| What are some antigens of the enterobacteriacae? |
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| flagellar (H) capsule/fimbri (K) somatic=cell wall = LPS (O) |
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| What is the most common enterobacteriacae coliform? Describe some characteristics of it? diseases it causes? |
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| Escherichia coli enterotoxigenic enteroinvasive enteropathogenic (wasting disease of newborns) -infantile diarrhea -traveler's diarrhea |
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| what are some enterobacteriacae coliforms? |
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| -Klebsiella pneumonia -Enterobacter -Hafnia -Citrobacter -Serratia |
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| What diseases can Klebsiella pneumonia cause? |
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| nosocomial prneumonai, meningitis, bacteriemia, wound infections, UTI |
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| What diseases can -Proteus cause? |
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| UTI, wounds, pneumonia, septiciemia, infant diarrhea, burns |
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| What are some non-coliform pathogens that cause zoonoses |
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| Salmonella enteriditis S. paratypi S. schottmulleri S. hiirschfield S. typhimurium |
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| Describe -Salmonella typhi. What does it cause? |
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| gram negative noncoliform pathogen. cause typhoid fever. motile. adheres to mucosa of small intestine, progressive invasion that leads to septicemia, then to the lympht nodes, then to the liver and spleen, and ultimately cause bacteremia. causes fever, diarrhea, abdominal pain |
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| Describe -Shigella |
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| noncoliform pathogen. gram negative. causes shigellosis (sever abdominal cramps, watery stool with mucus and blood). also shigella dysentery when it invates the villi of the large intestine. non-motile, no capsule, not fastidious, no H2S or urease. |
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| what are some virulence factors of -Shigella |
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| endotoxin- fever enterotoxin. causes inflammation, degeneration of the villi, bleeding, heavy mucus production. Shiga toxin- heat-labile exotoxin infective dose = 200 cells |
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| Describe -Yersinia pestis |
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| Nonenteric. Causes plague. Gram negative rod. Bipolar stain. |
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| What are some virulence factors of Yersinia pestis |
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| capsular and envelope proteins protect against phagocytosis and promote intracellular growth. also coagulase, endotoxin. |
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| What are the three types of plague? |
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| 1. bubonic- bite to lymph node, inflammation = bubo. fever, chills, nausea 2. septicemic: coagulate blood in vessels, subcutaneous hemmorage, purpura to necrosis to gangrene 3. pneumonic: lungs, fatal |
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| What are the oxidase-positive nonenteric pathogens? |
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| -pasteurella multocida (zoonose) -haemophilus -h. influenza -h. aegyptius -h. ducreyi |
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| Describe -Haemophilus |
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| tiny gram-negative pleomorphic rods. fastidious, sensitive. REquire blood for hemitin (x factor), cytochromes, catalase, peroxidase |
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| what does -h. influenza cause |
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| acute bacterial meningitis |
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| what does -h. aegyptius cause? |
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| conjunctivitis/pink eye. subconjunctival hemorrhage |
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| what does -h. ducreyi cause |
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| chancroid -STD- painful necrotic ulcer on genitalia. lymph nodes swell like buboes. |
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| What viruses cause the common cold |
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| rhinoviruses and coronaviruses- no cure |
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| What virus causes influenza (the flu) |
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| influenza (H1N1)- vaccination - avian and swine flu. cause by RNA viruses transmitted through the air |
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| What virus causes Rabies (describe) |
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| Rabies virus causes acute encephalitis spread through animal bites travels to the brain by following the peripheral nerves fatal once it reaches the CNS and symptoms begin to show |
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| What viruses cause the common cold |
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| rhinoviruses and coronaviruses- no cure |
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| What virus causes influenza (the flu) |
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| influenza (H1N1)- vaccination - avian and swine flu. cause by RNA viruses transmitted through the air |
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| What virus causes Rabies (describe) |
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| Rabies virus causes acute encephalitis spread through animal bites travels to the brain by following the peripheral nerves fatal once it reaches the CNS and symptoms begin to show |
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| What virus causes chicken pox |
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| varicella-zoster virus |
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| Describe yellow fever |
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| virus that is transmitted through the bite of the Aedes species of mosquitos. causes jaundice, fever, damaged liver and sometimes kidney fever. has a vaccine that can prevent it for ten years. |
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| What viruses cause pneumonia |
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| influenza virus A and B, Respiratory syncytial virus (RSV), and Human parainfluenza viruses (in children). can get into the lungs and respiratory system, causing fever and difficulty breathing. |
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| What virus causes polio (describe) |
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| poliomyelitis. acute viral infectious disease spread from person to person via the oral-fecal route. 90% of polio infections cause no symptoms. Range of symptoms if it enters the bloodstream. Oral vaccines given for treatment. |
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| What virus causes Measles (Rubeola)-describe |
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| paramyxovirus of the genus Morbillivirus. enveloped, single-stranded, negative-sense RNA virus. Symptoms include fever, cough, runny nose, red eyes and rash. Contracted through the air like the flu. White dots in the throat are common. Vaccines available. |
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| Describe rotavirus |
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| the most common cause of severe diarrheal disease in infants and young children globally. accounts for more than half a million deaths a year due to dehydration. General double-stranded RNA virus. Vaccines available. |
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| Describe norovirus |
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| RNA virus that causes 90% of epidemic non-bacterial outbreaks of gastroenteritis around the world. REsponsibel for 50% of all foodborne outbreaks of gastroenteritis in the US. Transmitted by faecally contaminated food or water, person to person contact, or aerosolization of the virus and contamination of surfaces. |
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| Describe herpes virus |
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| sexually transmitted disease that affects one in five adults in the US. infects nerves and has cycles of infection. The structure of the herpes viruses consist of a relatively large double-stranded, linear DNA genome encased within an icosahedral protein cage called a capsid, which is wrapped in a lipid bilayer called the envelope. |
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| Describe hepatitis |
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| type A and B have vaccines types A through E are common can be spread through improper food handling and needle sharing. Viral hepatitis can be caused by Hep A-E, herpes simplex, cytomegalovirus, Epstein-barr, yellow fever, and adenoviruses. |
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| Describe yellow fever virus |
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| spread by mosquitos. common problem in tropical areas. causes jaundice. there is a vaccine, but no treatment once someone is infected. fifty percent die once they are in teh toxic phase. |
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| describe viral encephalitis |
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| encephalitis = swelling aroudn the brain. viral sources are transmitted by mosquito bites. vaccine available. |
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| describe west nile virus |
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| transmitted by mosquitos. brain swelling and death are common. |
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| describe HIV/AIDS |
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| highly transmissible virus. can sit quietly in the immune system within our cells for many years. can mutate form one person to another, making it hard to develop a vaccine. Transmitted through blood transfusions, unprotected sex, sharing needles. There are now HIV vaccinations that make AIDS more survivable. |
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| describe human papillomavirus |
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| common STD that is hard to test for in men. More than 30-40 types are transmitted through sexual contact and infect the anogenital region. Closely associated with genital wards but is also linked to cervical cancer. There is a vaccine. |
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| Describe mumps (virus) |
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| painful swelling of the salivary glands (parotid gland). disease is self-limiting, no specific treatment besides controlling the symptoms with painkillers. |
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| define prodrome (medicine) |
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| an early symptom or set of symptoms that might indicate the start of a disease before specific symptoms occur. |
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| Describe rubella (virus) |
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| german measles. infection fot eh mother during pregnancy can be serious. child may be born with congenital rubella syndrome, which is a range of serious incruable illnesses. Spontaneous abortion can occur in up to 20% of cases. |
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| Describe SARS virus |
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| Severe acute respiratory syndrome. Caused by the SARS coronavirus. |
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| Describe the structure of viruses |
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| contain a single type of nucleic acid (DNA or RNA) and a protein coat, sometimes enclosed by an envelope composed of lipids, proteins, and carbohydrates. |
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| Describe how viruses work |
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| they are obligatory intracellular parasites. they multiply by using the host cell's synthesizing machinery to cause the synthesis of specialized elements that can transfer the viral nucleic acid to other cells. |
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| What does host range mean |
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| the spectrum of host cells in which a virus can multiply. most viruses infect only specific types of cells in one host species |
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| What is host range determined by |
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| the specific attachment site on teh host cell's surface and the availability of host cellular factors |
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| what is the viral size |
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| 20 to 1000 nm in length. ascertained by electron microscopy. |
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| Describe the nucleic acid of viruses |
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| viruses contain either DNA or RNA, and the nucleic acid may be single or double stranded, linear or circular, or divided into several separate molecules. |
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| Describe viral capsids and envelopes |
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| the protein coat surrounding the nucleic acid of a virus is called the capsid. the capsid is composed of subunits, capsomeres, which can be a single type of protein or several types. The capsid of some viruses is enclosed by an envelope consisting of lipids, proteins, and carbs. Some envelopes are covered with carb-protein complexes called spikes. |
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| Describe helical viruses |
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| ex: ebola virus. resemble long rods, capsids are hollow cylinders surrounding the nucleic acid |
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| Decribe polyhedral viruses |
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| ex: adenovirus many-sided. usually the capsid is an icosahedron |
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| Describe enveloped viruses |
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| covered by an enveope and are roughly spherical but highly pleomorphic. enveloped helical viruses: influenza enveloped polyhedral viruses: Simplexvirus |
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| Describe complex viruses |
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| have complex structures. many bacteriophages have a polyhedral capsid with a helical tail attached. |
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| How are viruses classified |
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| based on what type of nucleic acid, their strategy for replication and their morphology |
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| How are virus families and genuses named |
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| family names end in -viridae; genus names end in -virus |
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| What is a viral species |
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| a group of viruses sharing the same geneticf information and ecological niche |
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| how are viruses grown |
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| in living cells |
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| what are the easiest viruses to grow |
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| bacteriophages |
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| what is the plague method |
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| a method to grow viruses in the lab. mixes bacteriophages with host bacteria and nutrient agar. after several viral multiplication cycles, the bacterial in the area surroudnign the original virus are destroyed; the area of lysis is called a plaque. each plaque originates with a single viral particle; teh concentraion of viruses is given as plaque-forming units |
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| Describe some aspects of growing animal viruses in the lab |
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| sometimes requires whole animals. simian AIDS and feline AIDS provide models for studying human AIDS. some animal viruses can be cultivated with embryonated eggs. viral growth can cause cytopathic effects in cell culture. |
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| what are cell cultures |
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| cells growing in culture media in the lab |
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| how can viruses be identified |
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| serological tests RFLPs PCR |
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| describe viral multiplication |
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| viruses do not contain enzymse for energy production or protein synthesis. For a virus to multiply, it must invade a host cell and direct the host's metabolic machinery to produce viral enzymes and components. |
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| describe the lytic cycle |
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| a phage causes the lysis and death of a host cell. |
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| describe lysogeny |
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| some viruses can have their DNA incorporated as a prophage into the DNA of the host cell. |
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| Describe the attachment phase of the lytic cycle |
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| sites of the phage's tail fibers attach to complementary receptor sites on the bacerial cell. |
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| Describe the penetration phase of the lytic cycle |
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| phage lysozyme opens a portion of the bacterial cell wall, the tail sheath contracts to force the tail core thorugh the cell wall, and phage DNA enters the bacterial cell. Capsid remains outside. |
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| Describe the biosynthesis phase of the lytic cycle |
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| transcription of phage DNA produces mRNa coding for proteins necessary for phage multiplication. Phage DNA is replicated, and capsid proteins are produced. |
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| Describe the eclipse period of the lytic cycle |
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| separate phage DNA and protein can be found. |
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| Describe maturation during the lytic cycle |
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| phage DNA and capsids are assembled into complete viruses. |
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| Describe the release phase of the lytic cycle |
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| phage lysozyme breaks down the bacterial cell wall, and the new phages are released. |
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| Describe the lysogenic cycle |
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| prophage genes are regulated by a erpressor coded for by the prophage. The prophage is replicated each time the cell divides. |
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| What can cause a cell to switch from the lysogenic cycle to the lytic cycle |
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| exposure to certain mutagens can lead to excision fothe prophage and initiation of the lytic cycle. |
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| What are the effects of lysogeny |
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| lysogenic cells become immune to reinfection with the same phage and may undergo phage conversion |
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| How can a lysogenic phage transfer bacterial genes |
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| A lysogenic phage can transfer bacterial genes form one cell to another through transduction. Any genes can be trasnferred in gernealized transduction, and specific genes can be trasnferred in specialized transduction. |
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| how do animal viruses attach to the host |
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| they attach to the plasma membrane of the host cell |
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| how does entry of animal viruses occur |
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| receptor-mediated endocytosis or fusion |
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| Where does multiplication of animal viruses occur |
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| int eh cytoplasm of the host cell |
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| What does retroviridae reverse transcriptase do |
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| transcribes DNA from RNA |
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| How are viruses relased in animal cells |
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| budding= method of release adn envelope formation nonenveloped viruses are released through ruptures in the host cell membrane |
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| what transforms normal cells to concerous cells |
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| activated oncogenes |
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| What are oncogenic viruses |
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| viruses capable of producing tumors |
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| what can a provirus do |
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| remain latent, produce viruses, or transform the host cell |
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| what is a latent viral infection |
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| one in which the virus remains in teh host cell for long periods without producing an infection (cold sores and shingles) |
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| what are persistent viral infections |
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| disease processes that occur over a long period and are generally fatal. caused by conventional viruses; viruses accumulate over a long period |
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| what are prions |
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| infectious proteins first discovered inteh 1980's. |
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| what do prion diseases involve? examples? |
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| involve the degeneration of brain tissue. CJD and mad cow disease |
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| what causes prion diseases |
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| they are the result of an altered protein. teh cause can be a mutation in the normal gene for PrPC or contact with an altered protein . |
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| How to plant viruses enter the host |
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| through wounds or with invasive parasites like insects |
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| what are viroids |
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| infectious pieces of RNA that cause some plant diseases, sucha s potato spindle tuber disase and cocanut cadang cadang viroid |
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| describe contagious cancer |
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| a parasitic cancer or transmissibe cancer is a cancer cell or cluster of cancer cells that can be transmitted form animal to animal. ex: devil facial tumour disease. |
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| what are pathogens |
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| disease-causing microbes |
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| what is pathology |
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| the study of disease |
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| what etiology |
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| the cause of disease |
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| what is pathogenesis |
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| the development of disease |
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| what is infection |
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| the invasion and growth of pathogens in the body |
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| what is disease |
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| an abnormal state in which part or all of hte body is not properly adjusted or is incapable of performing its normal functions |
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| define normal microbiota |
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| microbes that establish permanent colonies inside or on teh body without producing disease |
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| define transient microbiota |
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| microbes that are present for various periods and then disappear |
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| what is microbial antagonism |
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| when normal microbiota prevent pathogens from causing an infection |
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| what is symbiosis |
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| living together (normal microbes and the host) |
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| what is commensalism |
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| one organism benefits, the other is unaffected |
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| what is mutualism |
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| both organisms benefit |
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| what is parasitism |
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| one organism benefits at the expense of the other |
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| example of commensalism |
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| staphylococcus epidermidis on the skin and corynebacteria that inhabit the surface of the eye |
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| example of mutualism |
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| e.coli that synthesizes vitamins K and B in the gut |
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| example of parasitism |
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| disease-causing bacteria |
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| what are opportunistic microbes |
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| microbes that do not cause disease under normal conditions but cause disease under special conditions (e.coli) |
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| What are Koch's postulates |
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| 1. the same pathogen must be present in every case of the disease 2. the pathogen must be isolated in pure culture 3. the pathogen isolated from pure culture must cause the same disease in a healthy, susceptible lab animal 4. teh pathogen must be re-isolated from the inoculated lab animal |
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| what are some exceptions to Koch's postulates |
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| 1. things that cannot grow on artifical media 2. some disease have unequivocal signs and symptoms 3. some disease (pneumonia) may be caused by a variety of microbes 4. some pathogens (S. pyogenes) can cause different diseases. 5. some diseases (HIV) affect humans only. |
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| what are symptoms |
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| subjective changes in body functions |
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| what are signs |
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| objective changes (measurable) |
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| what is a syndrome |
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| a specific group of symptosm or signs that always accompanies a specific disease |
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| how are communicable diseases transmitted |
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| directly or indirectly from one host to another |
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| what is a contagious disease |
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| one that is easily spread |
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| what is disease incidence |
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| number of people contracting the disease |
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| what is disease prevalenec |
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| number of cases at a particular time |
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| what is an acute disease |
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| one that develops rapidly but lasts a short time (influenza) |
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| what is a chronic disease |
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| develops slowly, but is likely to continue or recur for long periods (tuberculosis, hep B) |
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| what is a subacute disease |
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| one that is intermediate between acute and chronic (sclerosing panencephalitis) |
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| what is a latent disease |
answer
| oen in which the causative agent remains inactive for a time but then becomes active to produce symptoms (shingles) |
question
| what is herd immunity |
answer
| the presence of immunity to a disease in most of the population |
question
| what is a local infection |
answer
| affects a small area of the body |
question
| what is a systemic infection |
answer
| spread throughout the body via the circulatory system. |
question
| what is a focal infection |
answer
| a local infection that spread systemically to another spot on the body, where it is located. |
question
| what is a primary infection |
answer
| an acute infection that causes the initial illness |
question
| what is a secondary infection |
answer
| one that can occur after the host is weakened from a primary infection |
question
| what is an inapparent or subclinical infection |
answer
| one that does not cause any signs of disease in the host |
question
| what is a predisposing factor |
answer
| something that makes the body more susceptible to disease or alters the course of a disease (age, gender, climate, fatigure, poor nutrition) |
question
| what is the incubation period |
answer
| the interval between the initial infection and the first appearane of signs and symptoms. |
question
| what is the prodromal period |
answer
| characterized by the appearane of teh first mild signs and symptoms |
question
| what is the period of illness |
answer
| the diease is at its height,a nd all disease signs and symptoms are apparent. |
question
| what is the period of decline |
answer
| the signs and symptoms subside |
question
| what is the period of convalescence |
answer
| the body retursn to its prediseased state and health is restored. |
question
| what are the five stages to the development of a disease |
answer
| 1. incubation period. 2. prodromal period. 3. period of illness 4. period of decline 5. period of convalescence. |
question
| what is a reservoir of infection |
answer
| a continual source of infection |
question
| what are zoonoses |
answer
| diseases that affect wild and domestic animals and can be transmitted to humans |
question
| what is droplet transmission |
answer
| transmission via saliva or mucus in coughing or sneezing. |
question
| what is vehicle transmission |
answer
| transmission by a meidum such as water, food, or air |
question
| what is airborne transmission |
answer
| pathogens carried on water droplets or dust for a distance greater than one meter |
question
| how do arthropod vectors transmit disease |
answer
| 1. mechanical (flies carrying the diease on them, spores, etc.. ex: cholora) 2. biological (malaria) |
question
| what is a nosocomial infection |
answer
| any infection tha tis acquired during the course of stay in a hospital |
question
| what is a health care associated infection |
answer
| include infections that are acquired in a setting other than a hospital |
question
| how many hospital patients acquire nosocomial infections |
answer
| 5-15% |
question
| how are normal microbes responsible for nosocomial infections |
answer
| when they are introduced into the body through such medical procedures as surgery and catheterization |
question
| what bacteria are the most frequent causes of nosocomial infections |
answer
| opportunistic, drug-resistant, gram-negative bacteria |
question
| how are nosocomial infections transmitted |
answer
| through direct contact between staff members and patients and between patients, and through fomites such as catheters, syringes, and respiratory devices. |
question
| what are emerging infectious diseases |
answer
| new diseases and diseases that are increasing in incidence |
question
| what leads to emerging infectious diseases |
answer
| the use of antibiotics and pesticides, climatic changes, travel, the lack of vaccinations, and improved case reporting |
question
| who is responsible for surveillance and response to emerging infectious diseases |
answer
| the CDC, NIH, and WHO |
question
| what is the science of epidemiology |
answer
| the study of the transmission, incidence, and frequency of disease |
question
| what is descriptive epidemiology |
answer
| data about infected people are collected and analyzed |
question
| what is analytical epidemiology |
answer
| a group of infected people is compared with an uninfected group |
question
| what is experimental epidemiology |
answer
| controlled experiments designed to test hypotheses are performed |
question
| what does case reporting do |
answer
| it provides data on incidence and prevalence to local, state, and national health officials |
question
| what is pathogenicity |
answer
| the ability of a pathogen to produce a disease by overcoming the defenses of the host |
question
| what is virulence |
answer
| the degree of pathogenicity |
question
| what is the portal of entry |
answer
| the specific route by which a particular pathogen gains access to the body |
question
| what is the parenteral route (portal of entry) |
answer
| when some microbes gain access to tissues by inoculation through the skin and mucous membranes in bites, injections, and other wounds. route of penetration |
question
| what are some common portals of entry |
answer
| mucous membranes of the conjunctiva and the respiratory, gastrointestinal, and genitourinary tracts. Most microbes cannot penetrate intact skin- they enter hair follicles and sweat ducts |
question
| what is the preferred portal of entry |
answer
| many microbes can cause infections only when they gain access through their specific portal of entry |
question
| what is LD50? |
answer
| lethal dose for 50% of the inoculated hosts - a way of expressing virulence |
question
| what is ID50? |
answer
| infectious dose for 50% of the inoculated hosts- a way of expressing virulence |
question
| how do pathogens adhere to the host? |
answer
| surface projections on a pathogen called adhesins (ligands) adhere to complementary receptors on the host cells. |
question
| what are adhesins |
answer
| surface projections on a pathogen. They can be glycoproteins or lipoproteins and are frequently associated with fimbriae. |
question
| What is the most common receptor on host cells for pathogens? |
answer
| mannose |
question
| what effect do biofilms have on pathogenicity? |
answer
| they provide attachment and resistance to antimicrobial agents |
question
| what is the purpose of a capsule |
answer
| they prevent the cell from being phagocytized |
question
| what is the function of proteins in the cell wall of pathogens? |
answer
| proteins in the cell wall can facilitate adherence or prevent a pathogen from being phagocytized |
question
| what does coagulase do? why is this important? |
answer
| local infections can be protected in a fibrin clot caused by the bacterial enzyme coagulase |
question
| what are kinases? |
answer
| enzymes that destroy blood clots and facilitate the spread of bacteria from a focal infection |
question
| what are hyaluronidases? |
answer
| bacterial enzymes that destroy a mucopolysaccharide that holds cells together and facilitates the spread of bacteria from a focal infection |
question
| what are collagenases? |
answer
| bacterial enzymes that hydrolyze connective tissue called collagen and that help bacteria spread from focal infections |
question
| what are the three enzymes that allow bacteria to spread from a focal infection |
answer
| kinases, hyaluronidase, and collagenase |
question
| what is antigenic variation |
answer
| when microbes vary their expression of antigens in order to avoid the host's antibodies |
question
| how to bacteria penetrate the host cell cytoskeleton |
answer
| bacteria may produce proteins that alter the actin of the host cell's cytoskeleton allowing bacteria into the cell |
question
| how do bacteria get iron from the host |
answer
| siderophores |
question
| how do bacterial pathogens directly damage host cells |
answer
| host cells can be destroyed when pathogens metabolize and multiply inside host cells |
question
| what are toxins |
answer
| poisonous substances produced by microorganisms |
question
| what is toxemia |
answer
| the presence of toxins in the blood |
question
| what is toxigenicity |
answer
| the ability to produce toxins |
question
| what are exotoxins |
answer
| toxins produced by bacteria that are released into the surrounding medium. They produce the disease symptoms, not the bacteria |
question
| what are antitoxins |
answer
| antibodies produced against exotoxins |
question
| describe A-B toxins |
answer
| they consist of an active component that inhibits a cellular process and a binding component that attaches to the two portions to the target cell. Ex: diphtheria toxin |
question
| what do membrane-disrupting toxins cause |
answer
| cell lysis Ex: hemolysins |
question
| what do superantigens do? |
answer
| they cause the release of cytokines, which cause fever, nausea, and other symptoms (toxic shock syndrome toxin) |
question
| What are endotoxins? |
answer
| lipopolysaccharides (LPS), the lipid A component of the cell wall of gram-negative bacteria |
question
| what causes the release of endotoxins |
answer
| bacterial cell death, antibiotics, and antibodies |
question
| what does the release of endotoxins cause |
answer
| fever (by inducing the release of interleukin-1) and shock (because of a TNF-induced decrease in blood pressure) |
question
| what do endotoxins allow bacteria to do? |
answer
| cross the blood-brain barrier |
question
| what is the Limulus amobocyte lysate assay used for? |
answer
| to detect endotoxins in drugs and on medical devices |
question
| what do plasmids do? |
answer
| carry genes for antibiotic resistance, toxins, capsules, and fimbriae |
question
| what can lysogenic conversion create? |
answer
| bacteria with virulence factors, such as toxins or capsules |
question
| how do viruses avoid the host's immune response? |
answer
| by growing inside cells |
question
| what are cytopathic effects (CPE)? |
answer
| visible signs of viral infections |
question
| what are cytocidal effects |
answer
| cell death caused by a virus |
question
| what are noncytocidal effects |
answer
| damage to the cell (but not death) caused by a virus |
question
| what are some cytopathic effects of viruses |
answer
| stopping mitosis, lysis, formation of inclusion bodies, cell fusion, antigenic changes, chromosomal changes, and transformation |
question
| what are symptoms of fungal infections caused by |
answer
| capsules, toxins, and allergic responses. |
question
| what are symptoms of protozoan and helminthic diseases caused by |
answer
| damage to host tissue or by the metabolic waste products of the parasite |
question
| how to some protozoa avoid destruction by the host's antibodies |
answer
| they change their surface antigens while growing in a host |
question
| what are some pathogenic properties of algae? |
answer
| some can produce neurotoxins that cause paralysis when ingested by humans |
question
| what are three common portals of exit for pathogens |
answer
| 1. the respiratory tract via coughing or sneezing 2. the gastrointestinal tract via saliva or feces 3. the genitourinary tract via secretions from the vagina or penis |
question
| what is a portal of exit for microbes in the blood |
answer
| arthropods and syringes |
question
| Describe the Aquificae bacteria |
answer
| thought to be the oldest branch of bacteria. Hyperthermophilic and Chemolithoautotrophic. They generate energy by oxidizing electron donors such as hydrogen, thiosulfate, and sulfur with oxygen as the electron acceptor |
question
| Describe the Thermotogae bacteria |
answer
| the second oldest branch of bacteria. Hyperthermophiles (80-90C). Gram negative rods with an outer sheath-like envelope that can balloon out from the ends of the cell. They grow in geothermal areas like marine hydrothermal vents. They are chemoheterotrophs with a functional glycolytic pathway. They can grow anaerobically on carbs and protein digests. |
question
| Describe the Deinococcus-Thermus bacteria |
answer
| Three genera- genus Deinococcus is the best studied. Spherical or rod-shaped, often associated in pairs or tetrads. They are aerobic, mesophilic, and catalase positive. They stain gram positive but have a layered cell wall and an outer cell membrane like gram negative bacteria. They are extremely resistant to desiccation and radiation. |
question
| Describe the biology of deinococci |
answer
| they can be isolated from ground meat, feces, air, fresh water, and other sources. they have a genome that consists of two circular chromosomes (a mega plasmid and a small plasmid) They have an unusual ability to repair chromosomal damage |
question
| What are the three groups of photosynthetic bacteria |
answer
| purple bacteria, green bacteria, and cyanobacteria |
question
| describe cyanobacteria |
answer
| they carry out oxygenic photosynthesis. they use water as an electron source for the generation of NADH and NADPH. They have chlorophyll a, which absorbs longer wavelengths of light. They are found mostly at the surface of bodies of water. |
question
| describe purple sulfur bacteria |
answer
| they use reduced sulfur compounds as electron sources and accumulate sulfur granules within their cells. They are anaerobes and use bacteriochlorophyll pigments. |
question
| describe green sulfur bacteria |
answer
| obligately anaerobic photolithoautotrophs. deposit sulfur granules outside of the cell. they lack flagella and are nonmotile. they are morphologically diverse. |
question
| describe purple nonsulfur bacteria |
answer
| they use organic molecules as their electron source. Anaerobic |
question
| Describe green nonsulfur bacteria |
answer
| filamentous, gliding bacteria. thermophilic. anoxygenic photosynthesis with organic compounds as carbon sources or can grou aerobically as a chemoheterotroph. |
question
| where are the photosynthetic pigments of cyanobacteria located |
answer
| in the thylakoid membranes |
question
| how do cyanobacteria fix carbon dioxide |
answer
| the calvin cycle |
question
| what pathway plays an important role in the metabolism of cyanobacteria |
answer
| the pentose phosphate pathway |
question
| what are trichomes (cyanobacteria) |
answer
| rows of bacterial cells that are in close contact with one another over a large area |
question
| how do cyanobacteria reproduce |
answer
| through binary fission, budding, fragmentation, and multiple fission |
question
| what does fragmentation create |
answer
| small motile filaments called hormogonia |
question
| what are akinetes |
answer
| thick-walled resting cells that are resistant to desiccation; they often germinate to form new filaments. formed by cyanobacteria |
question
| Describe the phylum Chlamydia |
answer
| nonmotile, coccoid, gram-negative bacteria. |
question
| how do chlamydia reproduce |
answer
| within the cytoplasmic vesicles of host cells by a unique developmental cycle involving elementary bodies and reticulate bodies |
question
| describe the genomes of chlamydias |
answer
| they have one of the smallest prokaryotic genomes |
question
| what are the three human pathogens in the Phylum Chlamydiae |
answer
| C. trachomatis, C. psittaci, and C. pneumoniae |
question
| What does Chlamydia trachomatis cause |
answer
| trachoma, nongonococcal urethritis, and other diseases in humans and mice |
question
| What does Chlamydia psittaci cause |
answer
| psittacosis in humans and infects many other mammals as well. invades the respiratory and genital tracts, the placenta, developing fetuses, they eye, and synovial fluid of the joints |
question
| What does Chlamydia pneumonia cause |
answer
| human pneumonia and possibly atherosclerosis and heart disease |
question
| Describe the Phylum Spirochaetes |
answer
| they are gram-negative, chemoheterotrophic, flexibly helical bacteria that exhibit a crawling motility due to a structure called an axial filament. |
question
| What are some important members of the Phylum Spirochaetes |
answer
| Treponema and Borrelia. T. Ppallidum causes syphilis B. burgdorferi causes Lyme disease |
question
| Describe the proteobacteria |
answer
| they are the largest and most diverse group of bacteria. Some believe that they arouse from a photosynthetic ancestor. |
question
| What are the five classes of the proteobacteria |
answer
| 1. Alphaproteobacteria 2. Betaproteobacteria 3. Gammaproteobacteria 4. Deltaproteobacteria 5. Epsilonproteobacteria |
question
| Describe the genera Rickettsia of the proteobacteria |
answer
| they are in the alphaproteobacteria. They are either parasitic or mutualistic. They enter the host by phagocytosis, escape the phagosome, and then reproduce in the cytoplasm by binary fission. The host cell eventually bursts and releases the new organisms. |
question
| What does Rickettsia ricketsii cause |
answer
| rocky mountain spotted fever |
question
| Describe Rhizobium leguminosarum |
answer
| they are proteobacteria that grow symbiotically within the root nodules cells of legumes as nitrogen-fixing bacteroids |
question
| Describe the genus Agrobacterium of the family Rhizobiaceae |
answer
| they are not capable of nitrogen fixation. Invades crown, roots, and stems of many plants and transforms infected plant cells into autonomously proliferating tumors. |
question
| What does Agrobacterium tumefaciens cause |
answer
| causes crown gall disease by means of a tumor inducing plasmid |
question
| Describe the genus Neisseria of the class Betaproteobacteria |
answer
| they are nonmotile, aerobic, gram-negative cocci. They are inhabitants of the mucous membranes of animals and human pathogens. |
question
| What cause gonorrhea |
answer
| Neisseria gonorrhoeae |
question
| what causes bacterial meningitis |
answer
| Neisseria meningitidis |
question
| Describe the genus Bordetella |
answer
| gram-negative aerobic coccobacilli. Chemoorganotrophs with respiratory metabolism. They require organic sulfur and nitrogen in the form of amino acids for growth. They are mammaliam parasites that multiply in the respiratory epithelial cells. Betaproteobacteria |
question
| Describe Bordetella pertussis |
answer
| nonmotile, encapsulated species that causes whooping cough |
question
| What is the largest class of the proteobacteria |
answer
| gammaproteobacteria |
question
| Describe the genus Pseudomonas (gammaproteobacteria) |
answer
| aerobic respiratory chemoheterotrophs. some are major animal and plant pathogens (P. aeruginosa) |
question
| Describe the family Vibrionaceae (gammaproteobacteria) |
answer
| gram-negative, straight or curved rods with polar flagella. They are oxidase-positive and use D-glucose as their sole or primary carbon and energy source. They are aquatic. |
question
| Describe V. cholerae |
answer
| causes cholera. |
question
| Describe the order enterobacteriales |
answer
| consists of one family containing over 41 genera. they are all gram-negative, peitrichously flagellated or nonmotile, facultatively anaerobic, straight rods with simple nutritional requirements. |
question
| give some examples of enterobacteriales |
answer
| Escherichia, proteus, salmonella, shigella, enterobacter, serratia, erwinia, klebsiella |
question
| describe the class epsilonproteobacteria |
answer
| the smallest of the proteobacteria groups. contains one order with two families. Campylobacter and Helicobacter are the most important genera. They are microaerophiles, motile, helical or vibroid, gram negative rods. |
question
| describe the genus Campylobacter |
answer
| epsilonproteobacteria. C. jejuni- causes abortion in sheep and enteritis diarrhea in humans |
question
| describe the genus helicobacter |
answer
| epsilonproteobacteria H. pylori- cause of gastritis and peptic ulcer disease. produces large quantities of urease and urea hydrolysis appears to be associated with their virulence. |
question
| What is a lichen |
answer
| a combination of a green alga (or a cyanobacterium) and a fungus. |
question
| Describe protozoa |
answer
| they are unicellular, eukaryotic organisms |
question
| what is a trophozoite |
answer
| the feeding and growing stage of a protozoan |
question
| what is schizogony |
answer
| multiple fission: the nucleus undergoes multiple divisions before the cell divides |
question
| how do protozoans reproduce sexually |
answer
| through conjugation |
question
| what is protozoan encystment |
answer
| under certain adverse conditions, some protozoa produce a protective capsule called a cyst. it permits the organism to survive when food, moisture, or oxygen are lacking, when the temperature is not suitable, or when there are toxic chemicals present. |
question
| describe the nutritional requirements of protozoans |
answer
| they are aerobic heterotrophs, although many are capable of anaerobic growth. |
question
| what is a cytosome? |
answer
| a mouth-like opening found on ciliated protozoans |
question
| where does digestion take place on protozoans |
answer
| in membrane enclosed vacuoles |
question
| what is the name of a parasite that does not have mitochondria and creates cysts |
answer
| Giardia lamblia (protozoan). causes giardiasis. diagnosed by cysts in the feces. |
question
| what is the name for a protozoan that has an undulating membrane and lacks mitochondria |
answer
| Trichomonas vaginalis. |
question
| Describe euglenoids |
answer
| protozoans. photoautotrophs. they have a semirigid plasma membrane called a pellicle. move by means of a flagella at the anterior end. they have an eyespot to sense light. they are facultative chemoheterotrophs. |
question
| describe hemoflagellates |
answer
| protozoans that are blood parasites. they are transmitted by the bites of blood feeding insects and are found in the circulatory system of the infected host. Includes the genus Trypanosoma. |
question
| describe Amebae |
answer
| protozoans that move by extending blunt, lobelike projections of the cytoplasms called pseudopods. |
question
| what is the only pathogenic ameba |
answer
| Entamoeba histolytica- found in the human intestine. |
question
| describe the Apicomplexa |
answer
| protozoans that are not motile in their mature forms and are obligate intracellular parasites. (Plasmodium) |
question
| what is a sporozoite |
answer
| the infective stage of plasmodium |
question
| what is a merozoite |
answer
| progeny of sporozoites that can infect RBCs |
question
| what is a definitive host |
answer
| the host that harbors the sexually reproducing stage of the bug (mosquito for malaria) |
question
| what is the intermediate host |
answer
| the host in which the parasite undergoes asexual reproduction (the human for malaria) |
question
| describe ciliates |
answer
| protozoans that have cilia that are similar to but shorter than flagella. |
question
| what is the only ciliate that is a human parasite |
answer
| Balantidium coli- causes a rare type of dysentary |
question
| describe slime molds |
answer
| protozoans that are closely related to amebae. Two types: cellular and plasmodial. |
question
| Describe helminths |
answer
| multicellular eukaryotic animals that generally possess digestive, circulatory, nervous, excretory, and reproductive systems. |
question
| What differences can be made between parasitic helmintsh and their free-living relatives |
answer
| parasitic helminthes may lack a digestive system, their nervous system is reduced, their means of locomotion is reduced, and their reproductive system is often complex |
question
| describe the platyhelminths |
answer
| flatworms. classes of parasitic flatworms include trematodes and cestodes. |
question
| describe trematodes |
answer
| flatworms that are called flukes. they obtain food by absorbing it through their nonliving outer covering, called the cuticle. |
question
| describe cestodes |
answer
| called tapeworms. they are intestinal parasites. their head is called the scolex. their body is made of segments called proglottids. |
question
| describe nematodes |
answer
| protozoans. roundworms. males are smaller than females. most species are dioecious. |
question
| how do protozoans reproduce asexually |
answer
| fission, budding, or schizogony |
question
| how do cellular slime molds get their nutrition |
answer
| they ingest bacteria by phagocytosis |
question
| how do plasmodial slime molds get their nutrition |
answer
| they engulf organic debris and bacteria as it moves |
question
| what are the nematodes that infect humans with their larvae |
answer
| hookworms and Trichinella |
