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79 Cards in this Set
- Front
- Back
Essential nutrient |
any substances that must be provided to an organism |
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Macronutrients |
Macronutrients: Required in relatively large quantities, play principal roles in cell structure and metabolism (ex. C, H, O) |
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micronutrients |
Micronutrients: aka trace elements, present in smaller amounts and involved in enzyme function and maintenance of protein structure (ex. Mn, Zn, Ni) |
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How are nutrients categorized according to Carbon content? |
Inorganic nutrients: A combination of atoms other than C and H |
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define heterotroph |
Heterotroph: Must obtain C in organic form (nutritionally dependent on other living things) |
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define autotroph |
Autotroph: Uses inorganic CO2 as its carbon source (not nutritionally dependent on other living things) |
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what is the main source of atmospheric nitrogen (N2)? |
The air we breathe |
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in order for N2 to be used, it must be: |
converted to NH3 (ammonia) (the only form that can be directly combined with C to synthesize amino acids and other compounds) |
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O2 is a major component of ______ ______ and makes up ______% of the atmosphere. |
organic compounds |
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H is a major element in ____ organic and ______ inorganic compounds |
all |
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what are three things H does in the biochemistry of cells |
Maintaining pH |
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phosphorus in a key component in ___________ ________ and is also found in _____________ and _____________ |
nucleic acids |
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Describe sulfur sources |
Widely distributed throughout the environment in mineral form |
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what role does calcium play in microbial life? |
stabilizer of cell walls and endospores |
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potassium is important in |
protein synthesis and membrane function |
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what is a growth factor? |
Growth factor: An organic compound such as an amino acid, nitrogenous base, or vitamin that cannot be synthesized by an organism and must be provided as a nutrient |
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what are phototrophs |
Phototrophs- Microbes that photosynthesize |
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what are chemotrophs? |
Chemotrophs- Microbes that gain energy from chemical compounds |
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describe photoautotrophs |
Photosynthetic |
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what are the three types of chemoautotrophs |
chemoorganic autotrophs |
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what are chemoorganic autotrophs? |
Chemoorganic autotrophs- use organic compounds for energy and inorganic compounds as a carbon source |
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what are lithoautotrophs |
Lithoautotrophs- rely totally on inorganic minerals |
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what are methanogens |
produce methane from hydrogen gas and carbon dioxide |
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Most pathogenic organisms that we see are: |
chemoheterotrophs - they like organic carbon sources |
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Is it likely that a phototroph would be a pathogen? |
No |
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what are two examples of chemoheterotrophs? |
saprobes |
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Saprobes are _______ micro-organisms |
free-living - like fungi |
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how do most saprobes get their nutrition? |
they release enzymes to the extracellular environment and digest food particles into smaller molecules |
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define obligate saprobe |
Obligate saprobes- exist strictly on dead organic matter in soil and water |
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define facultative parasite |
Facultative parasite- when a saprobe infects a host, usually when the host is compromised (opportunistic pathogen) |
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what are the three types of parasites? Define |
Ectoparasites- live on the body |
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what is an obligate parasite? |
Obligate parasites- unable to grow outside of a living host |
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define autotroph |
Autotroph: Uses inorganic CO2 as its carbon source (not nutritionally dependent on other living things) |
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what is the main source of atmospheric nitrogen (N2)? |
The air we breathe |
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in order for N2 to be used, it must be: |
converted to NH3 (ammonia) (the only form that can be directly combined with C to synthesize amino acids and other compounds) |
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O2 is a major component of ______ ______ and makes up ______% of the atmosphere. |
organic compounds |
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H is a major element in ____ organic and ______ inorganic compounds |
all |
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what are the three cardinal temperatures of a given microbial species? |
Minimum temperature: the lowest temperature that permits a microbe’s continued growth and metabolism |
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define psychrophile |
A microorganism that has an optimum temperature below 15°C and is capable of growth at 0°C. |
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describe psychrotrophs or facultative psychrophiles |
grow slowly in cold but have an optimum temperature above 20°C. |
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describe mesophile |
An organism that grows at intermediate temperatures |
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most human pathogens are: |
mesophiles |
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describe thermophile |
A microbe that grows optimally at temperatures greater than 45°C |
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what are the two atmospheric gases that most influence microbial growth? Which one has the greatest impact of the two? |
O2 and CO2 |
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Define aerobe |
Aerobe: can use gaseous oxygen in its metabolism and possesses the enzymes needed to process toxic oxygen products |
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define obligate aerobe |
Obligate aerobe: cannot grow without oxygen |
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define facultative anaerobe |
Facultative anaerobe: an aerobe that does not require oxygen for its metabolism and is capable of growth in the absence of it |
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define microaerophile |
Microaerophile: does not grow at normal atmospheric concentrations of oxygen but requires a small amount of it in metabolism |
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define anaerobe |
Anaerobe: lacks the metabolic enzyme systems for using oxygen in respiration |
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define strict, or obligate anaerobe |
Strict, or obligate, anaerobes: also lack the enzymes for processing toxic oxygen and cannot tolerate any free oxygen in the immediate environment and will die if exposed to it. |
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define aerotolerant anaerobes |
Aerotolerant anaerobes: do not utilize oxygen but can survive and grow to a limited extent in its presence |
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what type of O2 descriptor applies to us? |
obligate aerobe |
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what type of O2 descriptor applies to orgs that die in the presence of any O2? |
strict or obligate anaerobe |
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what type of O2 descriptor applies to orgs that like a lower concentration of O2? |
microaerophile |
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what type of O2 descriptor applies to orgs that uses O2 in it metabolism but doesn't require it and can grow without it? |
facultative anaerobe |
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what type of O2 descriptor applies to orgs that have the fastest growth rate? |
aerobes |
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what are capnophiles? |
organisms that grow best at a higher CO2 tension than is normally present in the atmosphere |
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Majority of organisms live or grow in habitats between pH ___ and ___ |
6 and 8 |
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define halophiles |
Halophiles- prefer high concentrations of salt |
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define osmophiles |
Osmophiles- live in habitats with a high solute concentration |
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describe barophiles |
deep-sea microbes that exist under hydrostatic pressures ranging from a few times to over 1,000 times the pressure of the atmosphere |
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All cells require ___________ |
water |
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Most microbes live in _____ ____ |
shared habitats |
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define symbiosis |
A general term used to denote a situation in which two organisms live together in a close partnership |
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what are the three main types of symbionts? |
mutualism |
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define mutualism |
Mutualism: when organisms live in an obligatory but mutually beneficial relationship |
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define commensalism |
the member called the commensal receives benefits, while its coinhabitant is neither harmed nor benefited |
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define parasitism |
Parasitism: a relationship in which the host organism provides the parasitic microbe with nutrients and a habitat |
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what is satellitism? |
at type of commensalism when one member provides nutritional or protective factors needed by the other |
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define nonsymbiotic |
Organisms are free-living and relationships are not required for survival |
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what are the two types of nonsymbiotic relationships? |
synergism |
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define synergism |
Synergism: an interrelationship between two or more free-living organisms that benefits them but is not necessary for their survival |
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define antagonism |
an association between free-living species that arises when members of a community compete |
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Interrelationships Between microbes and Humans can be what type of relationship (s) |
commensal, parasitic, and synergistic relationships |
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describe the two levels of mircrobial growth |
Cell synthesizes new cell components and increases in size |
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what is the basis of microbial population growth? |
binary fission (basically mitosis) |
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define generation or doubling time |
The time required for a complete fission cycle |
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Each new fission cycle or generation increases the population by a factor of ____ |
2 |
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what can be a limiting factor in the growth rate of microbes? |
nutrients and waste products |