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77 Cards in this Set

  • Front
  • Back
Essential nutrient
any substances that must be provided to an organism
Macronutrients
Required in relatively large quantities, play principal roles in cell structure and metabolism (ex. C, H, O)
micronutrients
aka trace elements, present in smaller amounts and involved in enzyme function and maintenance of protein structure (ex. Mn, Zn, Ni)
How are nutrients categorized according to Carbon content?
Inorganic nutrients: A combination of atoms other than C and H
Organic nutrients: Contain C and H, usually the products of living things
define heterotroph
Must obtain C in organic form (nutritionally dependent on other living things)
define autotroph
Uses inorganic CO2 as its carbon source (not nutritionally dependent on other living things)
what is the main source of atmospheric nitrogen (N2)?
The air we breathe
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)
O2 is a major component of ______ ______ and makes up ______% of the atmosphere.
organic compounds
20%
(also a common component of inorganic salts)
H is a major element in ____ organic and ______ inorganic compounds
all
several
what are three things H does in the biochemistry of cells
Maintaining pH
Forming hydrogen bonds between molecules
Serving as the source of free energy in oxidation-reduction reactions of respiration
phosphorus in a key component in ___________ ________ and is also found in _____________ and _____________
nucleic acids
ATP
Phospholipids in cell membranes and coenzymes
Describe sulfur sources
Widely distributed throughout the environment in mineral form
Essential component of some vitamins
Amino acids- methionine and cysteine
what role does calcium play in microbial life?
stabilizer of cell walls and endospores
potassium is important in
protein synthesis and membrane function
what is a 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
what are phototrophs
Microbes that photosynthesize
what are chemotrophs?
Microbes that gain energy from chemical compounds
describe photoautotrophs
Photosynthetic
Form the basis for most food webs
what is a type of chemoautotrophs
methanogens
what are methanogens
produce methane from hydrogen gas and carbon dioxide
Archae
Some live in extreme habitats
Most pathogenic organisms that we see are:
they like organic carbon sources
i.e. lipids, carbs
Is it likely that a phototroph would be a pathogen?
No
what are two examples of chemoheterotrophs?
saprobes
parasites
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
how do most saprobes get their nutrition?
they release enzymes to the extracellular environment and digest food particles into smaller molecules
define obligate saprobe
exist strictly on dead organic matter in soil and water
define facultative parasite
when a saprobe infects a host, usually when the host is compromised (opportunistic pathogen)
what are the three types of parasites? Define
live on the body
Endoparasites- live in organs and tissues
Intracellular parasites- live within cells
what is an obligate parasite?
unable to grow outside of a living host
define autotroph
Uses inorganic CO2 as its carbon source (not nutritionally dependent on other living things)
what is the main source of atmospheric nitrogen (N2)?
The air we breathe
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)
O2 is a major component of ______ ______ and makes up ______% of the atmosphere.
organic compounds
20%
(also a common component of inorganic salts)
H is a major element in ____ organic and ______ inorganic compounds
all
several
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
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
define psychrophile
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.
describe psychrotrophs or facultative psychrophiles
grow slowly in cold but have an optimum temperature above 20°C.
describe mesophile
An organism that grows at intermediate temperatures
Optimum growth temperature of most: 20°C to 40°C
Temperate, subtropical, and tropical regions
most human pathogens are:
mesophiles
with optimum temperature between 30°C and 40°C
describe thermophile
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
what are the two atmospheric gases that most influence microbial growth? Which one has the greatest impact of the two?
O2 and CO2

O2 has greatest impact
Define aerobe
can use gaseous oxygen in its metabolism and possesses the enzymes needed to process toxic oxygen products
define obligate aerobe
cannot grow without oxygen
define facultative anaerobe
an aerobe that does not require oxygen for its metabolism and is capable of growth in the absence of it
define microaerophile
does not grow at normal atmospheric concentrations of oxygen but requires a small amount of it in metabolism
define anaerobe
lacks the metabolic enzyme systems for using oxygen in respiration
define strict, or obligate anaerobe
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.
define aerotolerant anaerobes
do not utilize oxygen but can survive and grow to a limited extent in its presence
what type of O2 descriptor applies to us?
obligate aerobe
what type of O2 descriptor applies to orgs that die in the presence of any O2?
strict or obligate anaerobe
what type of O2 descriptor applies to orgs that like a lower concentration of O2?
microaerophile
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
what type of O2 descriptor applies to orgs that have the fastest growth rate?
aerobes
what are capnophiles?
organisms that grow best at a higher CO2 tension than is normally present in the atmosphere
Majority of organisms live or grow in habitats between pH ___ and ___
6 and 8
define halophiles
prefer high concentrations of salt
define osmophiles
live in habitats with a high solute concentration
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
All cells require ___________
water
(only dormant, dehydrated cell stages tolerate extreme drying)
Most microbes live in _____ ____
They often involve _____ _____
shared habitats

nutritional interactions
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
what are the three main types of symbionts?
mutualism
commensalism
parasitism
define mutualism
when organisms live in an obligatory but mutually beneficial relationship
define commensalism
1 member receives benefits, while its coinhabitant is neither harmed nor benefited
define parasitism
a relationship in which the host organism provides the parasitic microbe with nutrients and a habitat
what is satellitism?
at type of commensalism when one member provides nutritional or protective factors needed by the other
define nonsymbiotic
Organisms are free-living and relationships are not required for survival
what are the two types of nonsymbiotic relationships?
synergism
antagonism
define synergism
an interrelationship between two or more free-living organisms that benefits them but is not necessary for their survival
define antagonism
an association between free-living species that arises when members of a community compete
Interrelationships Between microbes and Humans can be what type of relationship (s)
commensal, parasitic, and synergistic relationships
describe the two levels of mircrobial growth
Cell synthesizes new cell components and increases in size
The numer of cells in the population increases
what is the basis of microbial population growth?
binary fission (basically mitosis)
define generation or doubling time
The time required for a complete fission cycle
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
what can be a limiting factor in the growth rate of microbes?
nutrients and waste products