Microbiology Chapter 11
30. What is bacteriochlorophyll and in which organisms are they found?
BACTERIOCHLOROPHYLL is a unique type of chlorophyll found only in anoxygenic phototrophs. Found in PLANTS & ALGAE.
Why is Bifidobacterium important?
Bifidobacterium are found in the intestinal tract of breast-fed infants and are thought to provide a protective function by excluding disease-causing bacteria.
3. Define: chemoheterotroph, chemolithotrophs, obligate aerobes & chemoorganotrophs.
CHEMOHETEROTROPH: Organisms that use chemicals as a source of energy, & organic compounds as a source of carbon. CHEMOLITHOTROPHS: Oxidize reduced inorganic chemicals such as hydrogen gas (H2) to obtain energy. OBLIGATE AEROBES: Organisms that require O2 for growth; obtain energy using respiration exclusively, none can ferment. CHEMOORGANOTROPHS: Oxidize organic compounds such as glucose to obtain energy, those that grow anaerobically often use sulfur or sulfate as a terminal electron acceptor.
39. What diseases does Chlamydia and Chlamydophila cause?
Chlamydia trachomitis causes eye infections and an STD that mimics gonorrhea. Chlamydophila pneumoniae causes atypical pneumonia and Chlamydophila psittaci causes psittacosis, a form of pneumonia.
16. The earliest oxygenic prototrophs are thought to be?
Cyanobacteria
27. List the medically important members of the family Enterobacteriaceae.
E.coli, Klebsiella pneumoniae, Proteus, Salmonella enterica serotypes Enteritidis and Typhi, Shigella, Yersinia pestis, Haemophilus influenza ad ducreyi, Legionella pneumophila, and Pseudomonas aeruginosa. Life threatening systemic diseases include typhoid fever, caused by Salmonella enterica serotype Typhi, and both the bubonic and pneumonic forms of plague caused by Yersinia pestis.
36. What disease does Helicobacter pylori and Mycoplasma pneumoniae cause?
H. pylori causes duodenal ulcers and stomach cancer, while M. pneumoniae is responsbile for causing pneumonia, often called "walking pneumonia."
Which bacteria produce what chromogens?
spirillum
56. Endospores of Bacillus stearothermophilus are used in testing autoclave operation.
True
57. Streptomyces produces a number of antibiotics like Streptomycin, Erythromycin, Tetracycline.
True
46-50. Which of the following best matches the description?
A. Diarrhea- E.coli B. Tetanus- Clostridium tetani C. Gonorrhea- Neisseira gonorrhea D. Pneumonia- Klebsiella pneumoniae E. Typhoid fever- Salmonella typhi
51. True or False:The skin and oral cavity may have anaerobic microenvironments.
True
52. Bacteria and Archaea both have members that use sulfur compounds as a terminal electron acceptor.
True
58. Chlamydia occurs in two forms, a non-infectious reticulate body and an infectious elementary body.
True
33. What are chlorosomes and which organism are they found?
CHLOROSOMES: Structures that hold accessory pigments of the green sulfur bacteria that are found in the inner surface of the cytoplasmic membrane. Chlorosomes are found in GREEN SULFUR BACTERIA.
35. What are trichomes?
TRICHOMES: Filamentous cellular associations that may or may not be enclosed within a sheath (a tube that holds and surrounds a chain of cells). Motile trichomes glide as a unit.
What are endospores and which organisms produce them?
Endospores are heat-resistant dormant forms of bacteria that can only be killed by autoclaving at 132 C for one hour. The organsims that produce them are Bacillus and Clostridium.
5. What organisms produce hydrogen sulfide? (rotten-egg smelling gas)
Anaerobic chemoorganotrophs, more specifically, the SULFUR- AND SULFATE-REDUCING BACTERIA.
25. What are the characteristics of Pseudomonas aeruginosa?
It is medically the most significant species. It is a common opportunistic pathogen, meaning that it primarily infects people who have underlying medical conditions. Unfortunately, it can grow in nutrient-poor environments, such as water used in respirators, and is resistant to many disinfectants and antimicrobial medications. Because of this, hospitals must be diligent to prevent it from infecting patients.
14. Define anoxygenic photographs and the role they play in the environment. (Unsure of answer)
It is the use of hydrogen sulfide or organic compounds not water as a source of their electrons for reducing power to make NADPH and therefore do not generate oxygen. They have a unique type of chlorophyll called bacteriochlorophyll that absorb wavelengths that penetrates deeper than those for chlorophyll and are not used by other photosynthetic organisms.
anoxygenic phototrophs
Live in environments with little to no O2 yet light penetrates. They have a unique type of chlorophyll called bacteriochlorophyll.
34. Which organisms produce what types of dormant structures that allow them to withstand extreme conditions?
MYXOBACTERIA, which produce dormant MICROCYSTS, or Bacillus and Clostridium, bacteria that form endospores.
40. Which organisms are obligate intracellular parasites?
Rickettsia, Orientia, Ehrlichia, Coxiella, Chlamydia, Chlamydophila, and Wolbachia.
19. What are heterocysts and which species of Cyanobacteria uses it?
Species of ANABAENA protect nitrogenase (the enzyme that works in nitrogen-fixing) in specialized thick-walled cells called HETEROCYSTS that lack photosystem II & cannot make O2. The heterocysts of some species form at very regular intervals within the filament reflecting the ability of cells within a trichome to communicate.
26. What is unusual about Thermus and Deinococcus?
THERMUS: Have an UNUSUAL CELL WALLS that stains gram-negative. They are thermophilic; and this trait has been proven to be extremely valuable because of their heat-stable enzymes which is an integral part of the polymerase chain reaction (PCR). DEINOCOCCUS: This species is unique in their extraordinary resistance to radiation. One type can survive exposure to a dose several thousand times that lethal to a human being. Dose shatters genome into many fragments, yet bacterial enzymes are able to repair damaged DNA.
20. What do purple sulfur bacteria and filamentous sulfur-oxidizers both have in common?
They both accumulate sulfur as intracellular granules.
53. Anoxygenic phototrophs grow photosynthetically only under aerobic conditions.
False
31. Which Bacteria are chromogenic on agar? (Unsure of answer)
Pseudomonas species can produce different colored water soluble pigments.
18. What are nitrogenase?
The enzyme complex that catalyzes nitrogen fixation is destroyed by O2; therefore, nitrogen-fixing cyanobacteria must protect the enzyme from the O2 they generate.
23. What is the staining method used for Mycobacterium and Nocardia species?
Acid-fast
28. What are coliforms?
Enteric bacteria that characteristically ferment lactose are included in a group called coliforms. This is an informal grouping of certain common intestinal inhabitants such as E. coli that are easy to detect in food and water; for years regulatory agencies have considered them to be an indicator of fecal pollution.
54. Obligate aerobes may transform energy via fermentation.
False
8. Streptococcus pyogenes causes what disease/diseases?
• pharyngitis (strep throat) • rheumatic fever • wound infections • glomerulonephritis • streptococcal toxic shock
40. What is bioleaching?
A process used to recover metals. Bacteria oxidize insoluble metal sulfides, producing sulfuric acid. This lowers the pH which converts the metal to a soluble form.
4. What is the difference between anaerobic and aerobic chemolithotrophs?
ANAEROBIC CHEMOLITHOTROPHS: Cannot use oxygen (O2) as terminal electron acceptor, instead must employ an alternative such as carbon dioxide (CO2) or sulfur. AEROBIC CHEMOLITHOTROPHS: Organisms obtain energy by oxidizing reduced inorganic chemicals, using O2 as a terminal electron acceptor.
10. What is the difference between aerobic and anaerobic chemoorganotrophs?
ANAEROBIC CHEMOORGANOTROPHS: Numerous anaerobic bacteria obtain energy through fermentation. Oxidize organic compounds such as glucose to obtain energy & use sulfur or sulfate as electron acceptor. When they use sulfur as a terminal electron acceptor, they produce hydrogen sulfide (rotten-egg smelling gas). AEROBIC CHEMOORGANOTROPHS: Oxidize organic compounds to obtain energy, using O2 as a terminal electron acceptor.
How is acidithiobacillus important and not important to the environment?
Acidithiobacillus is important in bioleaching and preventing acid rain. It is detrimental by causing runoff that can kill trees, fish, and other wildlife.
The genus of bacteria that is able to fix nitrogen and form heterocysts is?
Cyanobacteria
12. Give the biochemical and morphological characteristics of disease-causing Streptococcus species.
Cocci that grow in chains of varying lengths. They inhabit the oral cavity as part of the normal microbiota. Some are pathogens like S.pyogenes which causes pharyngitits (strep throat) and other diseases. Unlike the streptococci that inhabit the throat, S. pyogenes is Beta-hemolytic, an important characteristic used to distinguish it from most members of the normal microbiota.
What organism is a primary producer of what by doing what?
Cyanobacteria are primary producers of oxygen by nitrogen-fixing, or breaking down elemental nitrogen.
29. What two bacteria genera may form endospores?
Genus Bacillus and Genus Clostridium.
15. Describe purple sulfur and green sulfur bacteria
PURPLE SULFUR • Gram negative organisms that can sometimes be seen growing as colored masses in a sulfur-rich aquatic habitats such as sulfur springs. • Use hydrogen sulfide to generate reducing power, although some species can use other inorganic molecules such as hydrogen or organic compounds (pyruvate). • Many are strict anaerobes and phototrophs, some can grow in absence of light aerobically, oxidizing reduced inorganic or organic compounds as a source of energy. • Cells are relatively large (5µm in diameter), some are motile by flagella. • May have gas vesicles that enable them to move to their preferred level in water column. • Most accumulate sulfur in granules and appear to be contained within the cell. • Representative genera of purple sulfur bacteria include Chromatium, Thiospirillum and Thiodictyon. GREEN BACTERIA • Gram negative organisms that are found in similar habitats to the purple bacteria. • Use hydrogen sulfide as a source of electrons for reducing power and form sulfur granules (granules form outside of the cell). • Accessory pigments of green sulfur bacteria are located in structures called chlorosomes. • Lack flagella but have gas vesicles. • All are strict anaerobes and none can be use a chemotrophic metabolism. • Representative genera include Chlorobium and Pelodictyon.
11. What is important about Propionibacterium & to what prokaryotic group does it belong?
Part of Anaerobic Chemoorganotrophs—Fermentation. • Gram-positive pleomorphic (irregular-shaped) rods that produce propionic acid as their primary fermentation end product. • They can also ferment lactic acid thereby extracting energy from the waste product of another bacteria. • Important in the dairy industry: Swiss cheese production. Propionic acid give cheese their typical nutty flavor & CO2 also from the fermentation creates the signature holes in cheese. • Propionibacterium species are also found in the intestinal tract and in anaerobic microenvironments on skin.
9. Describe the protective role that Lactobacilli play as normal flora of the vagina.
They break down glycogen in the vaginal lining in response to estrogen. This lowers the pH of the vagina, providing an acidic environment where bacteria cannot grow.
55. The most medically relevant member of Pseudomonas is P. aeruginosa.
True.
17. Why are Cyanobacteria important to the planet?
Cyanobacteria still plays an essential role in the biosphere. As primary producers, they harvest the energy of sunlight, using it to convert CO2 into organic compounds.
From chapter 10, what is an evolutionary chronometer?
DNA sequences are viewed as evolutionary chronometers, meaning that sequence differences provide a relative measure of the time elapsed since the organisms diverged from a common ancestor. This is because random mutations cause sequences to change over times. Thus, the more time that has elapsed since two organisms diverged, the greater the differences in the sequences of their DNA.
14. Define anoxygenic photographs and the role they play in the environment.
Earliest photosynthesizing organisms were likely ANOXYGENIC PHOTOTROPHS. Rather than using water as source of electrons when making reducing power for biosynthesis, they use hydrogen sulfide or organic compounds, therefore do not generate O2. Modern-day anoxygenic phototrophs are a phylogenetically diverse. They live in bogs, lakes, &upper layers of mud. Found in little or no O2 environments, but light still penetrates. Use unique type of chlorophyll called bacteriochlorophyll that absorb light at wavelengths that penetrate deeper than those for chlorophyll.
14. Define anoxygenic photographs and the role they play in the environment.
Earliest photosynthesizing organisms were likely ANOXYGENIC PHOTOTROPHS. Use hydrogen sulfide or organic compounds as source of electrons for reducing power (not water) so as to make NADPH & in the process no O2 is generated. Modern-day anoxygenic bacteria are phylogenetically diverse. They live in bogs (wetland, swamp), lakes, upper layers of mud. Found in little or no O2 environment, but light penetrates. Have a different photosystems than plants, algae, cyanobacteria. Use a unique type of chlorophyll called bacteriochlorophyll that absorb light at wavelengths that penetrate deeper than those for chlorophyll.
6. What are facultative & obligate organisms?
FACULTATIVE ANAEROBES: Preferentially use aerobic respiration if O2 is available, as an alternative they can ferment. Facultative means that the organism is flexible, in this case in its requirements for O2. OBLIGATE AEROBES: Have an absolute requirement for oxygen (O2). Obtain energy using respiration exclusively; none can ferment. OBLIGATE ANAEROBES: Cannot multiply if oxygen (O2) is present, often killed by brief exposure of air. About 99% of prokaryotes that inhabit the intestinal tract are obligate anaerobes.
32. What is Geosmin and what organisms produce it?
GEOSMIN: A chemical that produces a distinct "earthy odor" which makes drinking water taste odd. CYANOBACTERIA and STREPTOMYCES produce geosmin.
7. What are Lactic acid bacteria give examples & what makes them important?
LACTIC ACID BACTERIA: Gram-positive bacteria that produce lactic acid as major end product of fermentation. Can be distinguished from other bacteria that grow in the presence of O2 because they lack the enzyme catalase, hence sucepptibe to the effect of ROS like H2O2. e.g. STREPTOCOCCUS (oral cavity; normal microbiota), ENTEROCOCCUS (human & animal intestinal tract), LACTOCOCCUS (gram+, cheese&yogurt), LACTOBACILLUS(gram+ rod, mouth&vagina), & LEUCONOSTOC. • Most can grow in aerobic environments; but they only ferment. • Some are pathogenic (e.g., β-hemolytic S. pyogenes).
24. Which organism causes Hansen's disease (leprosy)?
Mycobacterium leprae
22. List the two mycobacterium species that cause disease in humans?
Mycobacterium tuberculosis and Mycobacterium leprae.
37. Organisms that typically produce colonies with a fried egg appearance are called?
Mycoplasma
44. Complex structures called fruiting bodies are a characteristic of what organism?
Myxobacteria
1. It has been estimated that 99% of the intestinal tract bacteria are?
Obligate anaerobes
What are chemotrophs?
Organisms that harvest energy by oxidizing chemicals.
21. What is the significant role of sulfur oxidizers to the environment?
They obtain energy by oxidizing elemental sulfur and reduced sulfur compounds. O2 is their terminal electron acceptor, which generates sulfuric acid. These bacteria are important in the sulfur cycle.
38. What disease does Treponema and Borrelia cause?
Treponema causes Syphillis, while Borrelia causes Lyme disease and relapsing fevers.
13. Clostridium, Lactobacillus, and Propionibacterium all have what in common?
They are all gram positive rods, anaerobes that grow in the absence of oxygen, involved with fermentation. They oxidize organic compounds and use organic compounds as terminal electron acceptors. • Members of the genus CLOSTRIDIUM: Gram positive rods that can form endospores. They are common inhabitants of the soil where their vegetative cells live in the anaerobic micro-environments created when the aerobic organisms consume available oxygen. A group of Clostridium species ferment a wide variety of compounds including sugars and cellulose. • Members of the LACTOBACILLUS: Rod shaped bacteria. Like the lactococci they are important in the production of fermented foods • PROPIONIBACTERIUM species: Gram positive pleomorphic rods that produce propionic acid as their primary fermentation end product. Species are valuable to the dairy industry because their end products play an indispensable role in the production of Swiss cheese. Propionic bacterium species are also found in the intestinal tract and in anaerobic microenvironments on the skin.