test two lec 9 part 1 Flashcards
when bacteria is faced with environmental stress, what happens
endospores
heterocysts
fruiting bodies
aerial hyphae
what species can produce dormant spores
clostridium and bacillus species
what are dormant spores resistant to
heat and dessication
clostridium causes
tetanus, botulism and diarrhea
baillus causes
anthrax
when do spores grow and need nutrients
when they germinate
starvation initiates an elaborate genetic program that involves
asymmetrical cell division process that produces a forespore which ultimately becomes and endospore
sporulation can be divided into discrete stages based on
morphological appearance
how do endospores survive
dessication: have less water than in vegetative state
packed with small acid soluble proteins that bind to and protect DNA from UV light and various toxic chemicals
what is germination
wakes cell, dissolves spore coat, releases viable vegetative cell
what is an anabaena
autotrophic cyanobacterium
makes O2 via photosynthesis and can fix N2 to make ammonia
what cyanobacterium uses heterocysts
anabaena
how do heterocysts work
ever 10th photosynthetic cell converts to this
loses ability to fix CO2 and forms envelop to limit O2 access
allows to fix nitrogen anaerobically while other cells maintain oxygenic photosynthesis
what are fruiting bodies
reproductive structure
what bacteria uses gliding motility
myxococcus xanthus
what triggers fruiting bodies
starvation triggers aggregation of 100000 cells
fruiting bodies are similar to
biofilms
cells in the middle of fruiting bodies differentiate into
spores to help find nutrient sources
gliding motility uses what for movement
swarming
light moltilty
what is sacrophutic
process dead/ decaying matter
differences in growth rates of organisms is determined by
nutrition and niche-specific physical parameters like temp and pH
where do slow growing microbes live
in low energy environments
what are mesophiles
grow in normal conditions
mesophiles grow in what conditions
20 to 40 celsiuse
neutral pH
.9% salt
ample nutrients
what are extremophiles
organisms inhabiting any ecological niche outside the normal window
what is the main criterion that a specie inhabits its environmental inhabitat
the tolerance of that organisms proteins other macromolecular structures to the physical conditions within that niche
can multiple extremes be met in one environment
yes
yellowstone hot spring
high acid/high alkalinity and high temp
does a bacteria cell’s temp match its immediate environment
yes
changes in temp of bacterias environment affects
molecular motion and impacts microbial physiology membrane fluidity nutrient transport DNA/RNA stability enzyme structure and function
what do each organism has that defines its growth limits
optimum temp
plus min and max temp
when does fastest growth rate occur regarding to temp
occurs at temps where all of the cells proteins work most efficiently as a group to produce energy and synthesize cell components
when does growth stop according to temp
when rising temp cause critical enzymes/ cell structures to fail
what happens to cell growth at cold temps
growth ceases bc processes slow down and the cell membrane is less fluid
why is the cell membrane when it is in a fluid state so important
for cell expansion and insertion of membrane transport proteins
if a microbe can grow at higher temp what does that mean for their rate of growth
they achieve higher rates of growth
temp for psychrophiles
0-25 celsius
temp for mesophiles
15 to 45 celsius
temp for thermophiles
45 to 80 celsius
temp for hyperthermophiles/ extreme thermophiles
80 to 121 celsius
how we know about pathoges, DNA/RNA, proteins, and membran came from the study of
mesophiles
what temp is human bacterial pathogens of mesophiles
37 celsius
what makes mesophiles good lab rats
don’t need high temp or high or low pressure
what type of environments do psychrophiles live in
arctic/antarctic
deep sea
what are the proteins like in psychrophiles
more flexible and require less energy (heat) to function
but they denature at lower temp than mesophiles
what are the membranes like of psychrophiles
more fluid
higher proportion of unsaturated fatty acids, kinks lipids dont pack as tightly
in psychrophiles what helps lower the freezing point
antifreeze proteins and cryoprotectants
what is so great about psychrophiles enzymes
used for commercial interest
hyperthermophiles was the first source of hight temp…
DNA polymerase
what hyperthermophile was isolated from hot spring at yellowstone national park
thermus aquaticus
what do thermophiles have that help them adapt
chaperone proteins
DNA binding proteins and enzymes to tightly coil DNA
membranes packed tightly
what are chaperone proteins
help refold other proteins as they undergo thermal denaturation
what kind of membranes do thermophiles have
more saturated linear lipids
packed more tightly
what are the enzymes like in thermophiles
dont unfold as easily
hold shape better at higher temp
low amts of glycine, enzymes less flexible
amino termini are tied down by H bonding to other parts of protein
makes protein harder to denature
what is heat shock response
rapid temp changes experienced during growth activates batches of stress response genes
what protein products are associated with heat shock response
chaperones and enzymes
heat shock response occurs in all
domains
bacteria and archea not so good in what temp
below 0 celsius and above 100 celsius
what is eukaryotes temp limits
10 to 65 celsius
what are protists upper temp limit
50 celsius
what are fungi upper temp lmit
60 celsius
mesophiles want to live at what pressure
sea level
barophiles and piezophiles live in what pressure
high pressure
1000 atm
barotolerant organisms grow well over the range of
1 to 50 MPa
but growth rate falls off after that
what are the adaptations that barophiles have to survive high pressure
higher levels of polyunsaturated fatty acids to increase membrane fluidity
unique ribosome structures to tolerate high pressure
microbes can only use what kind of water
water not bound to ions or other solute solution
what is water activity
a measure of how much water is available for use
how is osmolarity related to water activity
inversly
the more particles in solution the greater the
osmolarity and lower the water activity
what are aquaporins
membrane channel protein that allow water to traverse the membrane much faster than by diffusion
are aquaporins active transport
no but is passive
when are aquaporins used
during osmotic stress when cell needs water
what are the two ways microbes can minimize osmotic stress
import solutes or leak solutes
in a hypertonic media, bacteria protect their internal water by synthesizing or importing
compatible solutes that increase intracellular osmolarity
in hypotonic media, pressure sensitive or mechanosensitive channels can be used
to leak solutes out of cell
keep water from rushing in
most bacteria require salt concentrations of
0.1 to 1 M
halophiles require
high salt concentrations
2 to 4 M
halophiles use what to excrete Na+ and replace it with cations
special ion pumps
