definitions flashcard exam III

definitions flashcard exam III - 1. Microaerophile:...

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2/10/11 1. Microaerophile: Organisms that require O2 for respiration but can not grow under atmospheric concenterations. [ ex: Beggiatoa: a sulfur oxidizing organism, it is oxygen phobic. It chemotaxic away fromoxygen, so it tries to go where the concentration of oxygen is lower. Azospirillumv, Campylobacter, & capnophile organisms: typically can’t grown under air. Could be that there’s too much oxygen or too little CO2 2. Capnophile: Organisms that require increased levels of CO2 for growth. 3. Aerobe: Organisms that require O2 for growth and are capable of growing at atmospheric concentration (about 20%). [ ex : Micrococcus] 4. Anaerobe: Organisms that grows in the absence of O2. 5. aerotolerant anaerobe: an anaerobe with can also grow in the presence of O2 and they are evenly spread along the test tube. . [ ex: Streptococcus, Lactobacillus] 6. obligate anaerobe: anaerobic organisms that fail to grown in the presence of O2. 7. strict anaerobe: an anaerobe which is killed or inhibited by O2. [ ex: methanogens, sulfate- reducing bacter, Clostridium and organisms in the human’s guts] 8. facultative aerobe (anaerobe): organism that can utilize O2 for growth when it is present or grow in its absence. [ ex: Escherichia, Thiobacillus, Rhodobacter ] 9. magnetotactic: microaerophilic bacteria that can sense the earth’s magnetic field. These highly motile bacteria swim along the magnetic field— they are not “pulled” by the 10.Magnetosome: cytoplasmic inclusions of magnetic particles formed by magnetotactic bacteria; chains of 15- 20 particles · Magnetite ( Fe3O4) : ferromagnetic iron oxide, is the most magnetic of all the naturally occurring minerals on earth and it is found in magnetosome’s particles. · Greigite ( Fe3S4): iron sulfide, is magnetic It is a mixed-valence compound, 11. MamK: an actin-like protein found in some bateria, is required for the proper organization of the magnetosome chain. 12. triplet O2 : means that the molecules contains two unpaired electrons in the highest energy orbitals with the same spin which is ordinarily not very reactive.
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2/10/11 13. singlet O2: the electrons now have opposite spins which is much more reactive and the toxicity of singlet O2 is not firmly established. 14. Superoxide (O2-) : anion formed by one electron reduction of O2. A free radical. 15. hydrogen peroxide (H2O2): reactive molecules formed by a one electron reduction of superoxide. 16.hydroxyl radical (OH-): a free radical formed by a one electron reduction of H2O2 , extremely reactive and probably the major cause of O2 toxicity. 17.free radical: a compound with a single unpaired electron, generally extremely reactive. 18.superoxide dismutase:
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definitions flashcard exam III - 1. Microaerophile:...

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