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level: Microbial Groups

Questions and Answers List

level questions: Microbial Groups

QuestionAnswer
Aerotolerant anaerobe- organsim that doesn't use oxygen in metabolic rxns but can grow in its presence - an anaerobe that tolerates air (21% oxygen) - can detoify or excrete toxic oxygen products - some Lactobacillus spp, Enterococcus faecalis, Enterococcus faecium
Aerotolerant anaerobe- organsim that doesn't use oxygen in metabolic rxns but can grow in its presence - an anaerobe that tolerates air (21% oxygen) - can detoify or excrete toxic oxygen products - some Lactobacillus spp, Enterococcus faecalis, Enterococcus faecium
Aerotolerant anaerobe- organsim that doesn't use oxygen in metabolic rxns but can grow in its presence - an anaerobe that tolerates air (21% oxygen) - can detoify or excrete toxic oxygen products - some Lactobacillus spp, Enterococcus faecalis, Enterococcus faecium
Aerotolerant anaerobe- organsim that doesn't use oxygen in metabolic rxns but can grow in its presence - an anaerobe that tolerates air (21% oxygen) - can detoify or excrete toxic oxygen products - some Lactobacillus spp, Enterococcus faecalis, Enterococcus faecium
Aerotolerant anaerobe- organsim that doesn't use oxygen in metabolic rxns but can grow in its presence - an anaerobe that tolerates air (21% oxygen) - can detoify or excrete toxic oxygen products - some Lactobacillus spp, Enterococcus faecalis, Enterococcus faecium
Aerotolerant anaerobe- organsim that doesn't use oxygen in metabolic rxns but can grow in its presence - an anaerobe that tolerates air (21% oxygen) - can detoify or excrete toxic oxygen products - some Lactobacillus spp, Enterococcus faecalis, Enterococcus faecium
Psychrophile (T)- organism that can grow at 0 C, optimum 15 C or lower, max 20 C - commonly isolated from Arctic and Antarctic environments - enzymes, transport systems, and protein synthesis mechanisms of psychrophiles work well at cold temperatures - cytoplasmic membrane remains fluid at cold temps due to high levels of unsaturated fatty acids - many psychrophiles suffer from membrane disruption & leak cytoplasmic constituents
Psychrotroph (T)- an organism that can grow from from 0-7 C, optimum temperature between 20-30 C- maximum growth temperature 35 C- major spoilage organisms of refrigerated foods- Pseudomonas spp.
Mesophile (T)- an organism that grows optimally between 30-40 C - minimum growth at 15-20 C, maximum is 45 C - many human enteric pathogens that grow rapidly at human body temp - ex: Salmonella, Escheria coli, Shigella dysenteriae
Thermophile (T)- an organism that can grow at 55 C or higher, optimum temp between 55 - 65 C - minimum temp 45 C - ex: Bacillus stearothermophilus
Metabolism- sum total of all chemical rxns in living cells - catabolism and anabolism
Catabolism- break down - energy (ATP) generated by breaking bonds (stripping electrons from large molecules) - e- pass along an electron transport chain (ETC) in cytoplasmic membrane - ATP produced by special enzymes (ATPases) located in cytoplasmic membrane - some energy stored as ATP, remainder given off as heat
Anabolism- build up - microorganisms use simple molecules and ATP to synthesize complex molecules - ex: protein, DNA
ETC in microbes- if electron transport stops, microbial cell will stop growing and eventually die bc of its inability to make energy (ATP) - microorganisms must use a terminal e- acceptor at end of chain to remove electrons and maintain electron transport
TEA- terminal electron acceptor - aerobes: oxygen - anaerobes: nitrite, nitrate, sulfate
Aerobe- organism that uses oxygen in metabolic reactions - requires oxygen for growth - Pseudomonas spp.
Strict aerobe- grows only in the presence of air (21% oxygen) - Alteromonas putrefaciens
Anaerobe- cannot grow in the presence of air - can't use oxygen in metabolic reactions - oxygen is toxic - Clostridium botulinum, Bifidobacterium spp.
Microaerophile- requires a small amout of oxygen (5%) for growth - larger amounts of oxygen are toxic to this organism - anaerobic environment inhibits growth - Campylobacter jejuni
Facultative anaerobe- oxygen not req. but may use it if available - metabolically versatile organsim - can use oxygen or other compounds as a TEA - Salmonella spp, Listeria monocytogenes, Escherichia coli, Shigella spp, Vibrio spp
Aerotolerant anaerobe- organsim that doesn't use oxygen in metabolic rxns but can grow in its presence - an anaerobe that tolerates air (21% oxygen) - can detoify or excrete toxic oxygen products - some Lactobacillus spp, Enterococcus faecalis, Enterococcus faecium