Exam 3 MMG 421 questions and
answers graded A+ updated
Why do feast/famine modes exist in microbes? - correct answer ✔✔typically long periods of
starvation punctuated by short, transient growth periods
What is required to survive after food is depleted? - correct answer ✔✔Starvation survival
mode is required. It satisfies the maintenance energy requirements to stay alive after growth
Give an example of feast/famine survival - correct answer ✔✔microbial productivity in
unamended soil is low, only 3-4 generations per year for most chemoorganotrophic bacteria.
rapid growth only happens during short periods following by long periods of dormancy
What is required to survive under starvation? - correct answer ✔✔Survival strategies, protect
from environment
What are the two major adaptive starvation strategies? - correct answer ✔✔Differentiating
responses
Non-differentiating responses
What are differentiating responses? - correct answer ✔✔major morphological transformations
into dormant resting propagules (structures)
What are non-differentiating responses? - correct answer ✔✔less morphological differentiation,
but make numerous molecular modifications that enhance ability to survive, scavenge nutrients
and protect against many stresses
,What is bacterial sporulation? - correct answer ✔✔It is one example of bacterial differentiation,
triggered by unfavorable conditions
conversion of vegetative cell into non-reproducing resting propagule
How does bacterial sporulation help the organism survive? - correct answer ✔✔increases
survival/dispersal without increase in population size
most resistant form of life on earth, is the target for sterilization, survives extreme conditions
the vegetative cell producing the spore is the sporulating cel, the spore within the sporulating
cell is called the ENDOSPORE
What does bacterial sporulation result in? - correct answer ✔✔the conversion of a vegetative
cell into a non-growing, heat resistant, dormant endospore
What are some of the key events of sporulation? - correct answer ✔✔asymmetric partitioning
of the developing spore protoplast
engulfment of the spore protoplast by spore septum
formation of multiple spore coat layers
maturation of the core
8 hours
, What are some key features of endospores? - correct answer ✔✔They contain SASPs, Ca2+ for
dehydration, dipicolinic acid coat layers, and a primordial cortex
What are SASPs? - correct answer ✔✔small acid-soluble spore proteins
special proteins inside endospores, some are storage proteins degraded and utilized upon
germination, others bind and protect spore DNA
What causes the endospore to have thermoresistance? - correct answer ✔✔dehydration, 70 to
20% of dry weight
mineralization (Ca2+)
SASPs protection of DNA
What is special about dipicolonic acid? - correct answer ✔✔it is a unique abundant signature
component of endospores, it complexes with Ca2+ inside the spore coat
it is fluorescent?
What is Macromolecular turnover? (to generate metabolic energy) How controlled is it? What is
the advantage? - correct answer ✔✔Degradation of reserve polymers of PHB, glycogen, and
polyphosphate
highly controlled turnover of cellular things that are in less demand during non-growth
starvation
turning over just the expendable excess at the right rate without lethal consequences helps
survive longer
answers graded A+ updated
Why do feast/famine modes exist in microbes? - correct answer ✔✔typically long periods of
starvation punctuated by short, transient growth periods
What is required to survive after food is depleted? - correct answer ✔✔Starvation survival
mode is required. It satisfies the maintenance energy requirements to stay alive after growth
Give an example of feast/famine survival - correct answer ✔✔microbial productivity in
unamended soil is low, only 3-4 generations per year for most chemoorganotrophic bacteria.
rapid growth only happens during short periods following by long periods of dormancy
What is required to survive under starvation? - correct answer ✔✔Survival strategies, protect
from environment
What are the two major adaptive starvation strategies? - correct answer ✔✔Differentiating
responses
Non-differentiating responses
What are differentiating responses? - correct answer ✔✔major morphological transformations
into dormant resting propagules (structures)
What are non-differentiating responses? - correct answer ✔✔less morphological differentiation,
but make numerous molecular modifications that enhance ability to survive, scavenge nutrients
and protect against many stresses
,What is bacterial sporulation? - correct answer ✔✔It is one example of bacterial differentiation,
triggered by unfavorable conditions
conversion of vegetative cell into non-reproducing resting propagule
How does bacterial sporulation help the organism survive? - correct answer ✔✔increases
survival/dispersal without increase in population size
most resistant form of life on earth, is the target for sterilization, survives extreme conditions
the vegetative cell producing the spore is the sporulating cel, the spore within the sporulating
cell is called the ENDOSPORE
What does bacterial sporulation result in? - correct answer ✔✔the conversion of a vegetative
cell into a non-growing, heat resistant, dormant endospore
What are some of the key events of sporulation? - correct answer ✔✔asymmetric partitioning
of the developing spore protoplast
engulfment of the spore protoplast by spore septum
formation of multiple spore coat layers
maturation of the core
8 hours
, What are some key features of endospores? - correct answer ✔✔They contain SASPs, Ca2+ for
dehydration, dipicolinic acid coat layers, and a primordial cortex
What are SASPs? - correct answer ✔✔small acid-soluble spore proteins
special proteins inside endospores, some are storage proteins degraded and utilized upon
germination, others bind and protect spore DNA
What causes the endospore to have thermoresistance? - correct answer ✔✔dehydration, 70 to
20% of dry weight
mineralization (Ca2+)
SASPs protection of DNA
What is special about dipicolonic acid? - correct answer ✔✔it is a unique abundant signature
component of endospores, it complexes with Ca2+ inside the spore coat
it is fluorescent?
What is Macromolecular turnover? (to generate metabolic energy) How controlled is it? What is
the advantage? - correct answer ✔✔Degradation of reserve polymers of PHB, glycogen, and
polyphosphate
highly controlled turnover of cellular things that are in less demand during non-growth
starvation
turning over just the expendable excess at the right rate without lethal consequences helps
survive longer
