exam four (microbial ecology) Flashcards
same place, same species
population
populations living together (multiple species in one area)
community
what defines a niche (habitat)
location, nutrients available, what it interacts with
the ___ and _____ govern microbial growth in nature
resources and conditions
growth rate is variable because _____ of living are variable
conditions
microbes can store energy using ____ ___
storage polymers (growth rate will decrease but can remain viable)
involves transfer of electrons and play a key role in metabolic reactions
redox reactions
microbes play a critical role in ____ _____
carbon cycling
microbes create a _____; aggregation of microbes together (they love surfaces)
biofilm
assemblages of bacterial cells attached to a surface and enclosed in an adhesive matrix
biofilm
the matrix is protective because of (also nucleic acid and protein)
polysaccharide
the biofilm develops upwards and has ____ ____
water channels
the biofilm will get a signal and _____ will occur
dispersal
what does the matrix protect microbes from
antimicrobials and biocides; grazing (by protozoans and immune system; means being consumed) and other stresses (such as temp.)
the biofilm allows communication through
quorum senses
in a biofilm there is ____ whether it is a population or community (become very formidable)
diversity
three major places biofilms are found
environment, industrial and health
very thick biofilms with different layers of microbes (each layer has its own requirements); they are all supporting eachother
microbial mats
as you go deeper in biofilm ___ and ____ decrease
O2 and pH
terrestrial environments for microbes
soil and terrestrial subsurface (enclosed grounwater)
(soil layers) lots of organic matter and microbes
A horizon
(soil layers) little organic matter and less microbes
B horizon
(soil layers) undecomposed plants
O horizon
soil surrounding plant roots; high microbial abundance
rhizophere
soil is ____; many species which vary by soil type and geography;
complex
majority of soil bacteria
actinobacteria, proteobacteria, bacteroidetes
aquatic environments for microbes
freshwater and marine
microbes living in lakes or streams; seasonal changes in temp., the microbes affect oxygen and carbon cycles (what environment?)
in freshwater environemtns
input of sewage and other waste waters cause oxygen to rise; what happens?
bacteria increases and algae and cyanobacteria increase (overgrowth)
microbes present in freshwater
proteobacteria. actinobacteria, bacteroidetes and cyanobacteria
microbes live in more constant and cooler temp., low nutrient levels, results in fewer and smaller microbes
marine environment
coastal areas have terrestrial runoff, are shallow and phototropic; what grows there
chlorophyll
the marine environment has biological activity which uses up oxygen and demand exceeds availability (affects aerobes); this is called
oxygen minimum zone
open ocean; prokaryotic or eukaryotic
phototrophs
phototroph that is related to cyanobacteria and responsible for half the photosynthetic biomass (10^5 CFU/mL)
prochlorococcus
bacteria in open ocean grows under low nutrient levels; small
pelagibacter
there are 10x more ____ than cells in the open ocean
viruses
low temp, high pressure, low nutrient and light environment (sediments and hydrothermal vents)
deep sea environment
microbes present in deep sea
chemotrophs, piezophiles (high pressure), psychrophiles
what microbes in hydrothermal vents
thermophiles and hyperthermophiles (bacteria and archaea)
prolonged microbial interaction with other organisms
symbioses
microorganism benefits, host harmed
parasitic symbioses
one benefits , the other unharmed
commensal symbioses
both species benefit from interaction
mutualistic symbioses
a fungus (ascomycete) and phototroph (alga) are ____; the phototroph provides organic material and fungus provides anchor to grow
mutualism
microbe attaches to root and gives plant more nutrients (legume; nitrogen fixing)
rhizobia
agrobacterium and crown gall have a ____ symbioses
parasitic
infect insects and is heritable, it scews the sex ratio in mosquito (makes male mosquitoes; lessens transmission of diseases)
wolbachia
attine (leaf cutter) ants have a mutualism with fungus
the ant feeds the fungus and the fungus feeds the ant
another fungus (escovopsis) destroys leaf garden and bacteria ____ is added to inhibit escovopsis
actinobacterium (pseudomonocardia)
with the actinobacteria added to the leaf garden a _____ will grow to inhibit it
yeast
rumen is the cow stomach and cellulose is digested then, what helps it break down
celluloytic microbes (they release glucose)
the cud that is regurgitated is used by ____ for animal energy source
fermenters
