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79 Cards in this Set
- Front
- Back
Essential nutrient
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any substances that must be provided to an organism
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Macronutrients
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Macronutrients: Required in relatively large quantities, play principal roles in cell structure and metabolism (ex. C, H, O)
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micronutrients
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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?
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Inorganic nutrients: A combination of atoms other than C and H
Organic nutrients: Contain C and H, usually the products of living things |
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define heterotroph
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Heterotroph: Must obtain C in organic form (nutritionally dependent on other living things)
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define autotroph
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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)?
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The air we breathe
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in order for N2 to be used, it must be:
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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.
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organic compounds
20% (also a common component of inorganic salts) |
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H is a major element in ____ organic and ______ inorganic compounds
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all
several |
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what are three things H does in the biochemistry of cells
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Maintaining pH
Forming hydrogen bonds between molecules Serving as the source of free energy in oxidation-reduction reactions of respiration |
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phosphorus in a key component in ___________ ________ and is also found in _____________ and _____________
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nucleic acids
ATP Phospholipids in cell membranes and coenzymes |
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Describe sulfur sources
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Widely distributed throughout the environment in mineral form
Essential component of some vitamins Amino acids- methionine and cysteine |
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what role does calcium play in microbial life?
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stabilizer of cell walls and endospores
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potassium is important in
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protein synthesis and membrane function
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what is a growth factor?
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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
i.e. some amino acids |
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what are phototrophs
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Phototrophs- Microbes that photosynthesize
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what are chemotrophs?
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Chemotrophs- Microbes that gain energy from chemical compounds
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describe photoautotrophs
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Photosynthetic
Form the basis for most food webs |
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what are the three types of chemoautotrophs
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chemoorganic autotrophs
lithoautotrophs methanogens |
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what are chemoorganic autotrophs?
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Chemoorganic autotrophs- use organic compounds for energy and inorganic compounds as a carbon source
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what are lithoautotrophs
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Lithoautotrophs- rely totally on inorganic minerals
"rock eaters" |
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what are methanogens
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produce methane from hydrogen gas and carbon dioxide
Archae Some live in extreme habitats |
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Most pathogenic organisms that we see are:
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chemoheterotrophs - they like organic carbon sources
i.e. lipids, carbs |
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Is it likely that a phototroph would be a pathogen?
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No
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what are two examples of chemoheterotrophs?
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saprobes
parasites |
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Saprobes are _______ micro-organisms
they feed primarily on _____________ |
free-living - like fungi
organic detritus from dead organisms Decomposers of plant litter, animal matter, and dead microbes |
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how do most saprobes get their nutrition?
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they release enzymes to the extracellular environment and digest food particles into smaller molecules
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define obligate saprobe
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Obligate saprobes- exist strictly on dead organic matter in soil and water
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define facultative parasite
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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
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Ectoparasites- live on the body
Endoparasites- live in organs and tissues Intracellular parasites- live within cells |
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what is an obligate parasite?
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Obligate parasites- unable to grow outside of a living host
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define autotroph
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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)?
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The air we breathe
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in order for N2 to be used, it must be:
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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.
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organic compounds
20% (also a common component of inorganic salts) |
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H is a major element in ____ organic and ______ inorganic compounds
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all
several |
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what are the three cardinal temperatures of a given microbial species?
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Minimum temperature: the lowest temperature that permits a microbe’s continued growth and metabolism
Maximum temperature: The highest temperature at which growth and metabolism can proceed Optimum temperature: A small range, intermediate between the minimum and maximum, which promotes the fast rate of growth and metabolism |
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define psychrophile
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A microorganism that has an optimum temperature below 15°C and is capable of growth at 0°C.
True psychrophiles are obligate with respect to cold and cannot grow above 20°C. |
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describe psychrotrophs or facultative psychrophiles
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grow slowly in cold but have an optimum temperature above 20°C.
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describe mesophile
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An organism that grows at intermediate temperatures
Optimum growth temperature of most: 20°C to 40°C Temperate, subtropical, and tropical regions |
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most human pathogens are:
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mesophiles
with optimum temperature between 30°C and 40°C |
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describe thermophile
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A microbe that grows optimally at temperatures greater than 45°C
Vary in heat requirements General range of growth of 45°C to 80°C Hyperthermophiles- grow between 80°C and 120°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?
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O2 and CO2
O2 has greatest impact |
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Define aerobe
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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
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Obligate aerobe: cannot grow without oxygen
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define facultative anaerobe
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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
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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
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Anaerobe: lacks the metabolic enzyme systems for using oxygen in respiration
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define strict, or obligate anaerobe
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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
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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?
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obligate aerobe
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what type of O2 descriptor applies to orgs that die in the presence of any O2?
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strict or obligate anaerobe
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what type of O2 descriptor applies to orgs that like a lower concentration of O2?
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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?
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facultative anaerobe
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what type of O2 descriptor applies to orgs that have the fastest growth rate?
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aerobes
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what are capnophiles?
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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 ___
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6 and 8
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define halophiles
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Halophiles- prefer high concentrations of salt
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define osmophiles
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Osmophiles- live in habitats with a high solute concentration
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describe barophiles
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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 ___________
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water
(only dormant, dehydrated cell stages tolerate extreme drying) |
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Most microbes live in _____ ____
They often involve _____ _____ |
shared habitats
nutritional interactions |
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define symbiosis
symbionts |
A general term used to denote a situation in which two organisms live together in a close partnership
Members are termed symbionts |
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what are the three main types of symbionts?
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mutualism
commensalism parasitism |
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define mutualism
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Mutualism: when organisms live in an obligatory but mutually beneficial relationship
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define commensalism
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the member called the commensal receives benefits, while its coinhabitant is neither harmed nor benefited
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define parasitism
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Parasitism: a relationship in which the host organism provides the parasitic microbe with nutrients and a habitat
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what is satellitism?
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at type of commensalism when one member provides nutritional or protective factors needed by the other
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define nonsymbiotic
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Organisms are free-living and relationships are not required for survival
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what are the two types of nonsymbiotic relationships?
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synergism
antagonism |
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define synergism
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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
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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)
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commensal, parasitic, and synergistic relationships
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describe the two levels of mircrobial growth
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Cell synthesizes new cell components and increases in size
The numer of cells in the population increases |
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what is the basis of microbial population growth?
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binary fission (basically mitosis)
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define generation or doubling time
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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 ____
As long as the environment is favorable, the doubling effect continues at a ____ _____ |
2
constant rate |
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what can be a limiting factor in the growth rate of microbes?
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nutrients and waste products
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