Exam 2 New Flashcards
hyperpsychophiles
extremophile with a temperature of -10 degrees Celsius
example: Lake Vida, Antartica
psychophiles
extremophile with a temperature between 4 and 10 degrees Celsius
psychophiles
extremophile where metabolism is optimized for low temperature
-the membrane fatty acids have extreme unsaturation or branching… so MORE fluid
mesophiles
extremophile with a temperature of 37 degrees Celsius
-most important temperature
raising the temperature by adding heat
This denatures protein structure, melts DNA into single strands, and disrupts membranes
-a function of a mesophile
lowing temperature with cold
this makes proteins inflexible (denatures), slows metabolism to a crawl, and shatters membranes
-function of a mesophile
100 degrees Celsius
heat over this amount is Insufficient to kill endospores
thermophiles
extremophile with a temperature between 50 and 80 degrees Celsius
thermophiles
an extremophile where
- bacteria have HIGH optima growth temperatures
- proteins fold properly at high temps
- membranes are long, straight fatty acids… so LOW fluidity
hyperthermophiles
extremophiles with a temperature between 80 and 133 degrees Celsius
-has hydrothermal vents
hydrothermal vents
openings in the sea floor where heated mineral-rich water flows
- most ocean floor is barren (lifeless)
- “black smokers” - animals feed near them
- steep temperature gradient in rock
temperature, desiccation, oxygen, radiation, acidity, pressure, and chemicals
conditions that limit bacterial growth
oxygen
very toxic in the air
desiccation
very dry conditions…
-a limit of bacterial growth
protein function
low water concentration limits this…
-a function of desiccation
halo-tolerance curves
jellies (sugar), brines (salt), or curing (salt)…
high salt OR high solute concentration acts just like desiccation… this is shown through these:
halophiles
ponds with high salt concentration
>2M NaCl
-have a red color
archaea halobacterium
the red color in halophiles is due to the photosynthetic pigment of this extreme halophile
superoxide
this reacts with and damages all macromolecules it comes into contact with… DNA is the most common target because it is the largest macromolecule
respiration
this generates oxygen radicals
immune cells
these types of cells secrete radicals and hydrogen peroxide
superoxide dismutase (SodA)
this detoxifies radicals
-function of oxygen protection
catalase (KatF)
this converts hydrogen peroxide to water
-function of oxygen protection
Barophiles
DNA replication fails at high pressures. An example of this is because they THRIVE at high pressures
UV light
a powerful mutagen that force thymine-thymine dimers in DNA
acidophiles
have a low pH
examples: stomach acid, lemon juice, vinegar, bread
alkalophiles
have a high pH
examples: soap, ammonia, drain cleaner
poisons
- under chemicals
- they inactivate proteins
examples: heavy metals (silver, mercury, arsenic)
phenolics and detergents
These are examples of membrane disruptors
-function under chemicals
lysol
example of a phenolic
alcohols and halogens
these are examples of protein denaturants
-function under chemicals
ethanol and iodine
what is an example of an alcohol and a halogen protein denaturant
antibiotics
target structures or reactions required for bacterial growth, but NOT human growth
protein denaturants, poisons, membrane disruptors, and antibiotics
the four things under the chemicals section in notes
niche theory
theory that states: different microbes grow best under specific conditions
generalists
this growth strategy is flexible… so microbes can grow under a broad range of conditions
specialists
this growth strategy is NOT flexible… so microbes need specific growing conditions`
eutrophic
nutrient rich environments
-fast growers
oligotrophic
nutrient poor environments
-slow growers
transport
the movement of a molecule outside of the cell to inside the cell
SecYEG
integral membrane protein that forms complex pores
SecA
peripheral membrane protein that provides export power
signal sequence
secreted proteins have a motif that the secretion machinery recognizes for export which is called:
chaperones
proteins that control the folding of other proteins
FtsZ
this forms a contractile ring in the middle of a cell and its function is polymerization / to recruit division machinery
MinC
this inhibits FtsZ polymerization
MinD
this activated MinC and is a membrane bound anchor
MinE
a topological determinant
forms at the end of MinC shells and inhibits MinC, thus determining where FtsZ is positioned
-KEEPS MinC and MinD OUT
Noc
“nucleoid occlusion”
coats the chromosome and inhibits FtsZ from polymerizing over the chromosome (prevents chromosomes from being guillotined)
direct counting
this type of measurement for growth occurs under the microscope
viable counting
this type of measurement for growth occurs by spreading culture on petri plates and counting
spectrophotometry
this type of measurement for growth measures turbidity by shining light through a dense culture
flow cytometry
this type of measurement for growth occurs by counting individual cells with a laser
Direct Counting A&D
advantages:
- don’t need to grow cells
- works for ANY sample
disadvantages:
- cells must be evenly distributed
- cannot distinguish what cells are alive or dead
Viable Counting A&D
advantages:
- can measure number of viable cells
- colony forming units
disadvantages:
- only works for culturable bacteria
- clumping
- assumes each colony comes from a single cell
Spectrophotomery A&D
advantages:
- most rapid technique
- reliable
disadvantages:
- only works for culturable bacteria
- clumping
- indirect
flow cytometry
advantages:
- accurate
- can measure size
disadvantages:
- slow
- clumping
- dead cells
exponential growth
all components (i.e. lipids, carbohydrates, DNA, proteins, etc.) double at the same rate… so time between generations is the same
generation time
time required for a cell population to double in size
growth rate
This is species specific, so depends on:
- species of bacteria
- types of nutrients
- temperature
growth rate
ALWAYS CONSTANT for a particular species under a defined set of conditions
batch culture
is a closed system... nothing added or removed includes four stages: -lag phase -exponential phase -stationary phase -death phase
contaminated food and presence in labs
what is batch culture good for?
environment and continual flux of material and waste products
what is batch culture bad for?
lag phase
- occurs after the inoculation into fresh medium
- slow to no growth
- recovery period
- physiological adjustment
exponential phase
- steady state or balanced growth
- metabolism of all cells is the same
- cell number doubles at regular intervals
- only time you can calculate growth
stationary phase
- no net increase in population size
- cells stopped
- nutrient depletion/toxin accumulation
- stringent response
stringent response
occurs during stationary phase
-during starvation when amino acids run low and translation pauses when amino acids stop
RelA
a protein that bind to ribosomes and detects pausing during starvation
-synthesizes ppGpp
ppGpp
a single modified nucleotide that signals for starvation phase changes or the stringent response
-it’s magic spot is increased on TLC plates after starvation
decreased cell size, decreased membrane fluidity, increased cross linking, increased motility, sporulation, and recycled proteins
what does ppGpp trigger?
continuous culture
open system… fresh nutrients flow in and waste products flow out
continuous culture
cells stay in exp
