exam 2 Flashcards
what is cellular growth
individual cell is getting larger in preparation for replication
how to prokaryotes divide
binary division
how to eukaryotes divide
mitosis
in chemotaxis, how will a bacteria respond to no attractant or repellent
random run and tumble movement
in chemotaxis how will a bacteria respond to an attractant or repellent
directed movement
what type of gradient do bacteria sense
sense temporal NOT spatial
what happens to a bacterial cell if MCP binds a repellent
a signal will be sent to the cell to increase the amount of tumbling
if a repellent is present what happens to the rate of CheA autophosphorylation
if repellent, increases
if a repellent is present what happens to CheY
will be made faster
if a repellent is present what happens to CheY-P
will increase
if a repellent is present what happens to CheB
will increase
what is an adaptation circuit
gradient increases or decreases with time and tries constantly to bring gradient back to default
doing what changes the way MCP acts towards repellents or attractants
adding or removing methyl groups
what is the function of CheB-P
its a demethylase that removes methyl groups from MCP’s
what is the function of Che-R
its a methylase that adds methyl groups to MCP
what compound of MCP increases tumbling
CheY-P
what compound of MCP decreases methylation
CheB-P
what happens to methylation when there is a repellent present
methylation is decreased leading to decreased sensitivity of presence of repellent
what is the main function of MCP
determining if something is a repellent or an attractant
what is the function of CheZ
removes P from CheY-P
what is the function of CheW
helps CheA attach to MCP
what is CheA
accessory protein able to autophosphorylate (pull P off ATP and use P)
what compound interacts with Fli proteins in flagella to determine flagellar movement
CheY-P
what does MCP stand for
methyl accepting chemotaxis protein
how many methyl groups can generally be added to MCP
around 6
how can you modify an MCP transducer
by adding or removing methyl groups
what compounds are involved in the adaptation (transducer) circuit
CheR, CheA, CheW, CheB
what compounds are involved in the response circuit
CheA, CheW, CheY, CheZ
what is the purpose of having a transducer and a response circuit
they sense change in concentration over time and react to the change over time
with an attractant how does CheA respond
autophosphorylation decreases
with an attractant how does CheY-P respond
increases, increases tumbling
with an attractant how does CheB-P respond
increases, decreasing methylation
with an attractant increased methylation occurs leading to _____ sensitivity of MCP
decreased sensitivity
if the cell moves towards the stimulus ____ sensitivity
decreased
if the cell moves away from the stimulus ___ sensitivity
increased
what is the function of septum formation in a cell
its the physical division of the cell
what must occur first before the cell can properly divide
it must replicate its DNA
what are fimbrae
shorter and more numerous than flagella or pili and are thought to be involved in attachment to surfaces/other cells
what are pili
one to a few per cell, hollow tube made of pilin involved in attachment and/or conjugation
how did griffith show the prevention of phagocytosis
inject pneumonia to mice with capsule they die, inject the same thing but without a capsule into mice and they live
what are the types of glycocalyx
capsules and slime layers
how can you tell the difference between a capsule and a slime layer
by the degree of organization and the tightness of attachment to the cell
is a glycocalyx hydophilic or hydrophobic
hydrophilic
what makes up a glycocalyx
polysaccharides and/or polypeptides
what is the function of a glycocalyx
attaches cells to surfaces, prevents phagocytosis, prevents desiccation
what does glycocalyx literally mean
sugar crown, glycocalyx surrounds the cell in a sugar coating
what types of bacteria can produce endospores
a very restricted number of gram positive bacteria (ex. bacillus)
what is an endospore
for survival, NOT for reproduction. essentially and extra outer coat to protect
what do endospores contain
dipicolinic acid and calcium ion accumulation (these help in resistance)
explain the process of sporulation
vegetative cell DNA becomes more dense and lines up, plasma membrane surrounds replicated DNA, spore septum surrounds the isoated portion making a forespore, peptidoglycan forms between membranes, spore coat forms, endospore is released from cell
what is the function of the last steps of sporulation
they make the spore resistant
what is the function of calcium dipicolinate in an endospore
helps to old strands of DNA together and protects against heat denaturization
dehydrates the spore helps with chemical resistance since all the water is used up, prevents formation of things like H2O2
what are the two possible meanings of growth
cell growth or population growth
what are the basic requirements for any type of cell division
replication of DNA, partitioning of DNA, septum formation
describe in brief the process of binary fission
DNA replication, cell elongation, septum formation, formation of distinct walls, cell separation
whats different about the cytoskeleton of eukaryotes versus prokaryotes
prok do not have a cytoskeleton
what is the function of a divisome in prok
body involved in division of cell membrane and cytoplasm
what is the most common type of prokaryotic motility
flagella
what type of prokaryotes typically use an endoflagella
spirochetes
what are the types of taxis
chemotaxis, phototaxis, aerotaxis, osmotaxis
what kind of motility is not done within fluid environment
gliding motility
what is motility
how you move in your environment as a survival advantage
what is taxis
directed movement in either positive or negative
what is conesis
undirected movement
what is positive taxis
movement towards a stimulus
what is negative taxis
movement away from a stimulus
how can you detect flagellin
with H-antigen
what is a eukaryotic flaella
extension of cell membrane around the flagella (made of microtubules) (9+2)
what is a prokaryotic flagella
filament made of flagellin aggregated together into a flagella, not an extension of the cell, cell membrane does not surround (more like a plug)
what is the function of MOT proteins
harness energy from the PMF and channels ions (gives energy to rings to move)
what is the function of FLI proteins
located between C and MS rings and act as a switch to initiate or deactivate PMF (for movement of the rings)
what direction is CW
reverse
what direction is CCW
forward
what is the C ring
cytoplasm
what is the MS ring
membrane space
what is the P ring
peptidoglycan
what is the L ring
LPS ring (only in G-)
where does the turning force for a flagella come from
the C and MS rings
how many flagella for monotrichus
1 polar or 1 lateral
how many flagella for amphitrichus
1 flagella at each end of the cell
how many flagella for lophotrichus
tuft of flagella either on one end or on both ends
how many flagella for peritrichus
ring of flagella surrounding entire cell
what is a basal body
prokaryotic molecular protein based motor
what are stators in prok motility
stators are the same at MOT proteins
what is it called when there is random run and tumble with no direction
conesis
what changes the direction of bacteria while they tumble or while they stop running
brownian motion will reorient them
what type of motility do type 4 pili have
twitching motility
what protein makes up fimbrae
fimbrin
what protein makes up pili
pilin
what are characteristics of fimbrae
short, sticky, thin, numerous
what are characteristics of pili
1 or 2, longer, thicker, help with complete conjugation (exchange plasmal DNA)
what is the function of cytoplasmic inclusions
used for energy storage
what is the function of PHA in cytoplasmic inclusion
energy storage
what does PHA stand for
polyhydroxylalkanoate
what is sulfur used for in cytoplasmic inclusion
its common, specialized and is anoxygenic
what is glygogen used for in cytoplasmic inclusion
access carbon and nitrogen, cant pass membrane due to size, solute conc for osmosis
what is polyphosphate used for in cytoplasmic inclusion
granules
what is a divisome
its the body responsible for division of prok cells
where is the divisome located
cell membrane and cytoplasm
what is FTSz in prok homologous to in euk
tubulin (cytoskeletal elements)
what does homologous mean
common evolutionary function
what does analogous mean
similar function
what are microtubules of euk
chains of tubulin
what does FTSz do in prok
forms a ring on inner cytoplasm at the center of the cell (part of divisome)
what is the function of zipA
anchors FtsZ (kind of like its glue), and recruits other divisome proteins to the site
what is FtsA homologous to in euk
actin
what is FtsI analogous to in euk
penicillin bringing protein
what does fts stand for
filamentous temperature sensitive
what is the function of FtsK
DNA binding protein that helps to partition DNA
what shrinks the FtsZ ring
depolymerization (ring shrinks and pulls membrane along with it but not the cell wall)
what pinches the cell wall so the cell can split
FtsI (makes new cell wall material)
how does a cell know where to partition
by the min proteins (min C and min D oscillate moving pole to pole and this defines the center of the cell)
what is the function of minE
removes the inhibition set by minCD and allows septum formation
what must daughter cells do before they can divide themselves
they must grow to the size of the mother cell before they can divide
what is the function of MreB
cycles the cell and hits in specific places, where it hits FtsI is able to generate new cell wall (lengthens the cell)
why are cocci spherical not elongated
they have no MreB
what causes spirillum
cresentin (acts the same way as MreB but it causes spiral not elongation)
what does it mean that prok have a high biotic potential
they can increase their population size rapidly
what is unrestricted growth and how is it made possible
bacteria can grow as fast as they want and its possible if the best possible conditions are made available to the bacteria. only under perfect conditions
rate of population growth is proportional to _____
initial population
what kind of growth is binary fission
exponential
what is n
number of generations
what is t
time over which growth occurs
what is g
generation time
what is k
specific growth rate constant
what is N
population size
how do you calculate n
log(N/N0)=n*log2
how do you calculate N
N=N0*2^n
how do you calcuate g
g=t/n
whats another term for generation
division cycle
how do you calcuate change in population over time
(delta N/N)=kdeltat
how do you determine k
must be determined under set conditions
what are the different stages/phases of bacterial growth
lag, exponantial (log), stationary, death
if you grow an oragnism on a different media what also must you do
generate a new growth curve
when getting a growth curve what do you record growth as
CFU/mL
what does CFU stand for
colony forming units
what is lag
period of physiological adaptation
what is exponential (log)
unrestricted growth (growing as fast as it can with the given conditions)
what is stationary growth
where the bacteria will cap out because the growth becomes restricted
what is death phase
cannibalism of cannibals, extension of waste products, death will dominate
why are theoretical equations so important for bacteria
bacteria are so simple that they follow theoretical equations well (theo mimics real life)
what is balanced growth
during unrestricted growth if all chemical constituants increase by the same proportion over the same time interval (all chemical increasing at same rate)
what is optical density
absorbance
what is an example of why balanced growth is helpful
measure DNA of one cell then measure all DNA present to determine the number of cells
what is a direct method of measuring population growth
counting the number of cells directly or CFU’s directly
what is an indirect method for determining population growth
(assuming balanced growth)
turbidity, measure cell dry weight, measure cell constituants (ex measure all DNA)
what are factors that affect microbial growth
chemical and physical
what are chemical microbial growth factors
chemicals needed to be fed (nutrition)
what are physical microbial growth factors
pH, salt concentration, heat
what is shelfords law of tolerance
in order to survive and reproduce in environment everything it needs must be in a specific range of existance
what does it mean that a cell needs macronutrients and micronutrients
macro and micro refer to amount needed not size of the molecule
what macronutrients are needed
CHNOPS (g/L)
how much of a cell does CHNOPS make up
about 95% dry weight
what are growth factors for a cell
usually things like vitamins and other small organic molecules
what are the 4 major organic molecule families
carbohydrates, proteins, nucleic acids, lipids
what elements make up carbohydrates
c, o, h
what elements make up proteins
c, h, o, n
what elements make up nucleic acids
c, h, o, p, n
what elements make up lipids
c, h, o
what type of organic molecules are usually used for carbon skeletons
sugar or proteins
where can an organism get carbon from
either from organic molecules or from carbon dioxide
when are organisms that use organic carbon
heterotrophs
what are organisms that use inorganic carbon
autotrophs
where do heterotrophs (organic) get nitrogen
proteins
where do inorganic (autotroph) get nitrogen
ammonia, ammonium, nitrate
how does a heterotroph get P
uses inorganic since organic forms are toxic (NaP, phosphate)
where do autotrophs get P
NaP, Phosphate
how do heterotrophs get S
amino acids
how do autotrophs get S
sulfate salts
how do organisms get minor macronutrients
try to use as salts with other major macros ex. potassium phosphate
what are the micronutrients
mostly transition metals (zinc, copper, iron, boron)
what is the main function of micronutrients
catalytic capabilities to make enzymes properly active (catalyst so substrates can bind)
what is a cofactor
organic
what is a coenzyme
inorganic
what are examples of growth factors
some amino acids (NAD, FAD)
why would something need growth factors
if micro and macro cant meet needs then can be met with growth factors
what is the purpose of growth media
to provide nutrients so organisms can grow
what are the two types of media
complex media and defined media
what is a complex media
contains complex ingredients (ex. enzyme digests of proteins or blood)
when would you use a complex media over a defined media
when you want generalized growth
what is defined media
contains specific ingredients in known amounts (chemically defined recipe)
when would you use a defined media over a complex media
usually used in research since there is no nutrient variance
what kinds of organisms need defined media
fastidious molecular organisms (picky ones who need very specific nutrients)
what does optimum temperature mean
the temperature at which the growth rate of an organism is at its highest (reproduce fastest)
what are biochemical reactions driven by in MO
enzymes
what is membrane gelling and when does it occur
(think of olive oil) when membrane gets too cold it becomes solid, but at optimal temperature it is fluid and things can properly pass through the membrane
in order from lowest temp to highest temp what are the types of philes
psychrophile, mesophile, thermophile, hyperthermophile
what is the difference between facultative and obligate
facultative can tolerate , obligate requires
what are the pH philes
acidophiles, neutrophiles, alkalinophiles
what is an enterotoxin
an exotoxin produced by proteins of the cell and is released by the cell while they cell is still living
regarding halophiles, what are most microorganisms
non-halophiles meaning they dont like a lot of solute (salt)
what is an osmophile
solute (based on osmotic effects)
what is a xerophile
can they tolerate dry conditions
all halophiles are osmophiles but what makes this distinction
halophiles have to do with sodium osmoregulation while osmophiles in general deal with solute osmoregulation
which philes are of most medical importance of humans
nonhalophiles, neutrophiles, mesophiles
what are compatible solutes
an increase in the concentration of compatible solutes in a cell does not make things toxic for the cell (adjusts cell water activity)
what are some examples of compatible solutes
betanes, mannitol, glycerol
what are the classification types for oxygen tolerance
obligate aerobes, microaerophiles, facultative anaerobes, aerotolerant anaerobes, obligate anaerobes
what is the purpose of using a roll tube
keep the agar within slightly warmer than solidification temp so you can test oxygen requirements
what is obligate aerobes
only grows where these oxygen (required)
what is microaerophiles
can tolerate some oxygen but prefers not
what is facultative anaerobe
prefers oxygen but can tolerate no oxygen
what is aerotolerant anaerobe
doesnt give a fuck about oxygen
what is obligate anaerobe
cannot tolerate oxygen
how is there a difference between needing oxygen and not being able to have oxygen
oxygen is toxic and those who have ways to deal with it require it, if an organism doesnt have ways to deal with it then it cannot survive in its presence
what essentially is metabolism
electron transfers between molecules
how many electrons are requires to reduce O2 to H2O
4 electrons
what happens when only one electron added to O2
superoxide anion
a free radical and negatively charged O2 (anion)
what happens when 2 electrons added to O2
peroxide anion
negatively charged O2 (anion)
what happens when 3 electrons added to O2
hydroxyl free radical
no longer an anion but a free radical is present (most toxic)
how do organisms deal with toxic O2 derivatives
by producing enzymes
what are the main enzymes we deal with that help with toxic forms of oxygen
catalase (CAT) and superoxide dismutalase (SOD)
what enzymes do strict aerobes have
CAT and SOD
what enzymes do strict anaerobes have
none
what enzymes do facultative anaerobes have
CAT and SOD
what enzymes do aerotolerant anaerobes have
either CAT or SOD
what enzymes do microaerophiles have
a partially active SOD
