Internal and External to the Cell Wall (part 2) Flashcards
What does periplasmic stand for in periplasmic flagella
refers to space after the cell membrane but before the cell wall
Which group has periplasmic flagella?
Spirochetes
What kind of motility does periplasmic flagella allow for?
rigid, corkscrew motion
Why is the corkscrew motion useful for spirochetes?
they tend to have to move through gelatinous environments, so the corkscrew motion helps with that
T/F periplasmic flagella are amphotrichous
T
Explain how organisms with periplasmic flagella move
tufts fold back and line the surface of the cell, forming axial fibril/filaments which then intertwine with eachother
What is gliding motility?
adhesive protein that binds, a motor protein then comes behind it and pushes it forward
How do organisms with type IV fimbriae move?
extension comes out of external membranes, attaches then pulls in to move forwards
What is gliding motility facilitated by?
motor and adhesive proteins along a helical track
What two proteins are found in the helical intracellular protein track?
gliding motors, surface adhesion proteins
What is twitching motility?
extension comes out from external surface that attaches and contracts (extend, grab, contract)
What type of fimbraiae are associated with twitching motility
type IV
Why is it beneficial for bacteria to interact with host cell actin?
allows them to evade our immune system
how do bacteria interact with host cell actin?
become motile in our cells, break out, then use our own host cell actin to create their own means of travel
What is the cytoplasm?
dense gelationous solutions comprised mainly of water and supplemented with dissolved gases, amino acids, sugars, and salt
what is a nucleoid
area of the cell where DNA is aggregated
what are plasmids?
extrachromosomal pieces of DNA
what are ribosomes?
sites of protein synthesis
What is the difference in eukaryotic and prokaryotic ribosomes?
eukaryotes: 60S large, 40S small ribosomal subunits (generally referred to as 80S when combined)
Prokaryotes: 50S large and 30S small ribosomal subunits (overall referred to as 70S)
what does S stand for? what is it used for?
svedberg unit, used to understand the sedimentation rate under acceleration
What are the differences between the prokaryotic and eukaryotic cytoskeletons?
Eukaryotes: actin microfilaments, tubular microtubules
Prokaryotes: MreB microfilaments, FtsZ microtubules, CreS (crescentin) intermediate filaments
What is the prokaryotic cytoskeleton comprised of?
MreB, FtsZ, CreS
what are carboxysomes?
polyhedral, protein covered bodies
What are cyanobacteria?
phototrophs that produce food and oxygen for marine and freshwater ecosystems
What are thylakoid structures? what are they used for?
extensively folded membrane that contains chlorophylls and electron carriers.
used to obtain and soak up solar energy
Why are carboxysomes necessary for reactions to proceed in the thylakoid structures?
their protein covering is packed with rubisco, rubisco is necessary for carbon dioxide fixation in photosynthesis
what are storage bodies?
granules of organic or inorganic material that function to store energetic molecules or structural building blocks
What are gas vesicles? what organisms are they found in?
rigid enclosed cylinders that are impermeable to water, but freely permeable to gases. Found in planktonic and cyanobacteria
What are the walls of gas vesciles composed of?
GvpA, GvpC
what do gas vesicles allow for?
allow for bacteria to move freely. Affects bouyancy, take in gases to move up release gases to move down
What are some things storage bodies can contain?
poly-beta-hydroxybutyric acid, glycogen, polyphosphate, elemental sulfur
when is poly-beta-hydroxybutric acid made?
when cell comes into area high in carbon
when is glycogen made? it is a polymer of __________
when carbon is in excess, it is a polymer of glucose
Bacteria store elemental sulfur, but use _______ _______
oxidized sulfide
what are magnetosomes? what is their function?
contain magnetite that confers a magnetic dipole to the bacterial cell.
allows bacteria to be pulled along earths magnetic fields
What is the function of endospores?
protect the cell from heat, UV, toxic chemicals
What is the primary trigger of endospore formation? some other triggers
form when there is a loss of a macronutrient (C,O,P,N)
dessication, temperature variability
From outermost to innermost what are the layers of an endospore?
exosporium, spore coats, outer spore membrane, cortex, inner spore membrane, core
What two orders can form endospores?
bacillus, clostridiales
The combination of triggers works to phosphorylate a sporulation factor, what is this called?
Spo0A
once sporulation proceeds, the bacteria do what?
secrete toxic protein that lyses nearby cells in which Spo0A hasnt been activated, also secrete antitoxin protein so they dont die
what is the cortex composed of?
lossely linked peptidoglycan
what are spore coats composed of?
4-5 protein layers that are unique to endospores
what is the exosporium
thin protein covering (not always present)
what is the inner spore membrane?
cells plasma membrane
what are some features of the core?
metabolically inactive, significantly dehydrated
what causes the core to be dehydrated? how much water is left?
dipicolinic acid and calcium, 10-25%
What is germination, when does it occur?
revitalization of the cell, upon favorable conditions.
What are the three stages of germination?
activation, germination, outgrowth
