Microbio 303 exam questions and
answers graded A+
Producers and consumers and how they work together - ANS✅✅one organism produces a product
that another organism will consume
Syntropy - ANS✅✅Metabolic process by which two different organisms cooperate to degrade a
substrate
General pattern of degradation - ANS✅✅depolymerization and then either fermentation or
respiration.
Aerobic degradation - ANS✅✅Aerobic respiration predominates
Oxidized products such as CO2, nitrate, sulfate are produced
Monomers are converted into water and carbon dioxide
Catabolism of Methanogens - ANS✅✅Anaerobic respiration
Sources of electrons: Carbon dioxide, formate, alcohols, methylamines, methanol, and acetate are
all used to reduce methane
Electron donors: Hydrogen is most common
Products: Methane and water
Methanogenesis is more energetically favorable compared to Acetogenesis so it can win when
nutrients are low
Catabolism of Acetogens - ANS✅✅Anaerobic bacteria
Sources of electrons: Carbon dioxide
Electron donors: Multiple donors are possible, but Hydrogen is common
Products: Acetate and water
Sulfate reducers - ANS✅✅When sulfate is available, SRB will outcompete methanogens and
acetogens
Sources of electrons: acetate, lactate, carbonic acids, formate
Electron donors: organic acids - same thing as sources of electrons
, Products: hydrogen sulfide, water, and CO2
Synthophomonas - ANS✅✅oxidizes butyrate to acetate to make ATP
Fermentation interaction - ANS✅✅fermenters produce partially oxidized products which can be
used by acetogens, methanogens, syntrophs
Symbiosis - ANS✅✅intimate association between two different types of organisms
Commensalism - ANS✅✅one benefits, the other is neither harmed nor benefitted
Amensalism - ANS✅✅one benefits while the other is harmed (e.g. pathogenesis)
Functions of symbiotic microbes - ANS✅✅-Assimilation of major nutrients
-Provision of minor but essential nutrients
-Protection from predators or parasites or environmental stresses
-Role in reproduction
-Role in normal physiology
-Role in development - Immune system
role of microbes in the Beewolf Digger wasp - ANS✅✅Wasps lay eggs in underground burrows
The cocoons then encourage the growth of Actinomycetes, that in turn produce a cocktail of
antimicrobial compounds that prevent other bacteria from infecting the cocoons
Primary and Secondary symbionts of insects - ANS✅✅need for survival of insect, Provide amino
acids and/or vitamins to host
zebra fish - ANS✅✅Fish raised germ free develop normally until about 5 days post fertilization,
then show abnormalities
This can be rescued by microbiota
herbivores and microbes - ANS✅✅Mammals are their own are unable to extract most of the
nutrients available in plants
answers graded A+
Producers and consumers and how they work together - ANS✅✅one organism produces a product
that another organism will consume
Syntropy - ANS✅✅Metabolic process by which two different organisms cooperate to degrade a
substrate
General pattern of degradation - ANS✅✅depolymerization and then either fermentation or
respiration.
Aerobic degradation - ANS✅✅Aerobic respiration predominates
Oxidized products such as CO2, nitrate, sulfate are produced
Monomers are converted into water and carbon dioxide
Catabolism of Methanogens - ANS✅✅Anaerobic respiration
Sources of electrons: Carbon dioxide, formate, alcohols, methylamines, methanol, and acetate are
all used to reduce methane
Electron donors: Hydrogen is most common
Products: Methane and water
Methanogenesis is more energetically favorable compared to Acetogenesis so it can win when
nutrients are low
Catabolism of Acetogens - ANS✅✅Anaerobic bacteria
Sources of electrons: Carbon dioxide
Electron donors: Multiple donors are possible, but Hydrogen is common
Products: Acetate and water
Sulfate reducers - ANS✅✅When sulfate is available, SRB will outcompete methanogens and
acetogens
Sources of electrons: acetate, lactate, carbonic acids, formate
Electron donors: organic acids - same thing as sources of electrons
, Products: hydrogen sulfide, water, and CO2
Synthophomonas - ANS✅✅oxidizes butyrate to acetate to make ATP
Fermentation interaction - ANS✅✅fermenters produce partially oxidized products which can be
used by acetogens, methanogens, syntrophs
Symbiosis - ANS✅✅intimate association between two different types of organisms
Commensalism - ANS✅✅one benefits, the other is neither harmed nor benefitted
Amensalism - ANS✅✅one benefits while the other is harmed (e.g. pathogenesis)
Functions of symbiotic microbes - ANS✅✅-Assimilation of major nutrients
-Provision of minor but essential nutrients
-Protection from predators or parasites or environmental stresses
-Role in reproduction
-Role in normal physiology
-Role in development - Immune system
role of microbes in the Beewolf Digger wasp - ANS✅✅Wasps lay eggs in underground burrows
The cocoons then encourage the growth of Actinomycetes, that in turn produce a cocktail of
antimicrobial compounds that prevent other bacteria from infecting the cocoons
Primary and Secondary symbionts of insects - ANS✅✅need for survival of insect, Provide amino
acids and/or vitamins to host
zebra fish - ANS✅✅Fish raised germ free develop normally until about 5 days post fertilization,
then show abnormalities
This can be rescued by microbiota
herbivores and microbes - ANS✅✅Mammals are their own are unable to extract most of the
nutrients available in plants
