Microbial Development Flashcards
what state are bacteria in when environmental conditions are favorable
vegetative state so they replicate freely
what two forms does Caulobacter crescentus have
swarmer and the stalked
what is the swarmer form / what is the stalked form
has a single polar flagellum and is motile / is attached to a surface through the stalk & holdfast
which form functions as the mother cell / what does that allow
the stalked version / allows researchers to distinguish between the mother and daughter cells
what is the holdfast composed of / why is it so strong
made of polysaccharides and lives on surfaces that have high water flow so have to be super stuck
what is the chemoreceptor array
allows the cell to sense where attractants are - tells which way the flagella should rotate (through phosphorylation)
what is flagellar rotation driven by
the proton motive force - protons from periplasm move down concentration gradient to drive flagella
which way can the flagella rotate / what does each direction do
both counterclockwise and clockwise / clockwise makes them tumble, counterclockwise makes them swim straight
how is c-di-GMP involved in caulobacter crescentus
completely controls when it becomes a stalked cell - controls motility and surface attachment
what happens to motility when c-di-GMP concentration is elevated
they move towards a sedentary lifestyle - surface colonization (blocks flagellar motility, inhibits flagellar biosynthesis, promotes biosynthesis of biofilm)
which phase of the bacteria maintains a high concentration of c-di-GMP, why?
the mother cell so that the daughter cell can immediately begin swimming
how do phototrophs use light to generate oxygen
they run the glycolysis reaction in reverse and extract electrons from water to generate oxygen - and reduces the NADP+ electron carrier
what is often the limiting factor of photorphs / what is often the limiting factor of chemotrophs
nitrogen availability / glucose
what organisms are the only ones that can fix nitrogen from the air / how do they do it
microorganisms / they reduce atmospheric N2 gas to ammonia (NH3)
what is the enzyme that fixes nitrogen / what is dangerous about it
nitrogenase fixes nitrogen / it is extremely explosive when coming into contact with oxygen
