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305 Ch 5
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36
Biology
Undergraduate 3
09/13/2013

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Term
lack of 02 is
Definition
NOT EXTREME, presence can be considered extreme
Term
– Mesophiles
Definition
– Live at temp between 15-45 °C
– most bacteria; salmonella, staph all live on humans and live at our temps
– most pathogens
Term
– Psychrophiles (Cryophiles)
Definition
– ~15 °C or less optimum
– fluid (flexible unsaturated membranes
– flexible proteins
Term
– Thermophiles
Definition
– 55-70 °C optimum
– pcr enzymes bc they work at high temps
Term
– Hyperthermophiles (extreme thermophiles)
Definition
– 80 °C+ optimum
– Crosslinked saturated membranes
– Ether membrane structures instead of esters bc stronger bonds needed for high temps
– Rigid proteins
– Strain 121 (Geogemma barossii) *** know this
– 107 C to 121, like high temps, high pressure to evoid boiling
Term
– Osmotic stress →
Definition
plasmolysis: membrane/wall separate.
Term
plasmolysis
Definition
– Cells lyse. Bacteria with cell wall gives it some protection but if theres enough salt causes plasmolysis-> cell wall comes apart from membrane causing burst
Term
Normal salt levles
Definition
0.2-5% NaCl
– salmonella
Term
– Osmotolerant
Definition
– Not extremophiles
– Ex staphylococcus aureus lives on skin: 10% NaCl OK sweating causes salt on skin but this microbe can survive the high salt on skin
– Don’t like it but can TOLERATE it
Term
– Halophiles
Definition
3%+ NaCl
– Oceans/ a lot of marine bacteria . Will die w/out NaCl
Term
– Extreme halophiles
Definition
10-20% NaCl
– (great salt lake, dead sea, deep sea vents)
Term
– Neutralophiles
Definition
– Considered normal: pH 5-8 optimum is 7, most bacteria
Term
– Acidophiles
Definition
– pH<5
– ex: lactobacillus acidophilus (purple G+) pH 4, regulate proton gradient allows them to survive these conditions.
Term
– Alkaliphiles (alkalophiles)–
Definition
– pH 9+
Term
use of oxygen
Definition
Energy production with or without O2
• Aerobic respiration: O2 terminal electron acceptor
Oxygen is not organic
• Anaerobic respiration: Other inorganic terminal electron acceptor
• Fermentation: Organic terminal electron acceptor (carbons and H+)
Term
response to oxygen
Definition
• Strict aerobes, facultative anaerobes, microaerophiles, aerotolerant anaerobes, obligate anaerobes
Term
"use of oxygen" obtains energy from --
removes--
Definition
source (light, inorganic, and/or organic compounds)
electrons from chemical compounds,
– Eventually transferring them to terminal electron acceptors which leave the celll and or are used for other purposes
– pyruvate
Term
use of oxygen mechanisms are used by all microbes?
Definition
– Some microbes use only one mechanism; others may do all 3.
Term
respiration
Definition
– Use an electron transport system/chain (ETS/ETC) to make proton motive force (PMF)
Term
ETS/ETC
Definition
series of proteins and small molecules
– Bonds are broken when electrons transferred between ETS/ETC components
– Energy from bond-breaking pumps H+
– PMF= [H+] outside > [H+] inside membrane
Term
– Alternative to respiration=
Definition
Fermentation – No ETS/ETC
– Might be genetic or environmental thing
Term
– ATP (adenosine triphosphate) synthase uses energy stored in
Definition
– Oxidative phosphorylation
Term
3 mechanisms for use of oxygen
Definition
aerobic- best
anaerobic
fermentaion-worst
Term
aerobic respiration
Definition
– Electrons donated to inorganic terminal (final) electron acceptor 02 (o2 is reduced)
– Oxygen dependent
– Most efficient (most ATP)
– Final product= water
Term
– Anaerobic respiration
Definition
– Electrons donated to DIFFERENT inorganic terminal electron acceptors (NO3-, SO4-2, others)
– Oxygen independent
– Less effecient than aerobic respiration
– Final product: No2-, other inorganics
Term
fermentation
Definition
– No ETS/ETC (other proteins/enzymes involved)
– No H+ pumped, no ATP synthase
– Most inefficient : no (or very little) ATP produced
– Only substrate level phosphorylation
– Oxygen-independent
– Electrons donated to organic terminal electron acceptor (pyruvate c3H4o3
– Final product organics and or CO2
– Lactic acid
Term
Is oxygen on its own toxic?
Definition
No but it has toxic byproducts
Term
Toxic by products of O2=
1.
2.
3.
Definition
= “oxidative stress”
– O2 ·- radical (superoxide) radical
– H2O2 (hydrogen peroxide)
– HO· radical (hydroxyl) – reacts FAST
Term
Detoxification from O2 is by:
Definition
3 enzymes
SOD
Catalase, peroxidase
Term
SOD
Definition
superoxide dimutase consume superoxide radical but generates peroide (also toxic) Adds H+
Term
Catalase/ peroxidase
Definition
consumes peroxide: turns peroxide into water and oxygen. o2 and H20 can diffuse out freely
Term
strict obligate aerobe
Definition
-SOD and catalase/peroxidase
Req )2
Only aerobically ALWAYS NEED O2, always need those enzymes around to get rid of radicals.
Cant respire anaerobically, cant ferment
Ex: mycobacterium tuberculosis many cyanobacteria (anabaenous spiroidis), neisseria gonorrheae
Term
Facultative anaerobe
Definition
– Facultative anaerobe
– -sod and catalase/peroxidaze
– prefers to respire aerobically
– back up plan: respires anaerobically and/or ferments
– No o2- can still survive
– ex: salmonella typhimurium
Term
– Aerotolerant anaerobe
Definition
grow better with o2
SOD and catalase/peroxidase enzymes => can deal with reactive oxygen species
Doesn’t care about 02, not efficient at getting energy out of environment
Cannot respire and only ferments= obligate fermenters
Ex: Lactobacillus acidophilus, Streptococcus pyogenes
Term
– Microaerophile
Definition
Very little SOD and catalase/peroxidase
Req low (2-10%) levels of O2
Higher O2 levels toxic
Usually respire aerobically
Ex: Treponema pallidium
Term
– Strict (obligate) anaerobe
Definition
No SOD, catalase, peroxidase, O2 is toxic
Respire anaerobically and/or ferment
Do not respire aerobically
EX: clostridium perfringens
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