MICR 271 FINAL EXAM QUESTIONS AND
CORRECT ANSWERS!!
How do bacterial cells divide?
binary fission - replication of chromosome, cellular growth, daughter cells are pinched off
replication begins before d-cells are pinched off
How do bacterial cells age?
senescence...
-inherit old cell material from "old" pole (side of cell wall inherited from parent cell)
-inherit damaged DNA
-inherit damaged proteins
-activation of damage defence systems instead of growth systems
Distinguish between the growth behaviours in microbes in response to oxygen.
obligate aerobe - aerobic respiration (O2 required)
facultative aerobe - oxygen very useful and not necessary
aerotolerant aerobe - strictly fermentative metabolism (tolerate O2)
strict anaerobe - oxygen is toxic, use fermentative metabolism or anaerobic respiration
microaerophile - require 2-10% O2 for growth... >20% is toxic
What are the types of reactive oxygen species?
superoxide anion, peroxide, hydrogen peroxide, hydroxyl radical, hydroxyl ion
How do bacteria utilize nutrients?
carbon - convert carbon to organic molecules, break down dead organic molecules (and release
carbon via respiration)
nitrogen - nitrifying bacteria oxidize nitrogen to produce energy
What are the metabolic groupings of organisms?
,energy sources (energy)
carbon sources (cell mass growth)
electron sources (energy conservation)
What distinguishes how organisms obtain energy?
chemotropic - obtain energy from external
chemicals (energy)
phototropic - obtain energy from light (energy)
What distinguishes how organisms obtain cell mass?
autotrophic - obtain carbon from CO2 (cell mass)
heterotrophic - obtain carbon from organic compounds (cell mass)
mixotrophs - hetero/auto
What distinguishes how organisms conserve energy in biochemical processes?
Lithotrophic - reduce from inorganics (energy conservation)
Organotrophics - reduce from organic compounds
What distinguishes the metabolic groups used to name microbes?
photoautotrophs - plants, algae and cyanobacteria
photoheterotrophs - green or purple non-sulphur bacteria, some archaea
chemoautotrophs - hydrogen/sulfur/nitrifying bacteria, some archaea
chemoheterotrophs -
aerobic: fungi, pathogenic bacteria
anaerobic: protozoa, bacteria, archaea
fermentation: bacteria, yeasts, archaea
How do bacteria utilize nutrients in anabolic processes?
need an energy source, a carbon source, an electron source
, How do bacteria utilize nutrients in catabolic processes?
breakdown materials to conserve energy, to produce energy or to create cell mass
Why must peptidogylcan layers undergo continuous remodelling and restructuring?
rigidity.... cell wall will lyse otherwise
What are important factors for the survival of bacteria?
ability to adapt to environmental conditions
communication with one another to coordinate their activites
How do persister cells resist antibiotics?
shift their metabolism to create enough ATP to remain viable, antibiotics have not targets, once
antibs are gone, shift back to division focused metabolism
How do bacteria use anabolic or catabolic processes to survive and adapt?
anabolics to grow and divide
catabolics to create enough energy to survive
How do bacteria use quorum sensing?
signal using autoinducers: n-acyl homoserine lactones, autoinducers 2, Com X
use signals to coordinate metabolic functions to adapt and survive (ie make biofilm)
How does quorum sensing work in gram-negative bacteria?
autoinducer is taken into cell, binds to intracellular receptor, receptor protein acts as a
transcriptional regulator by binding to DNA and altering gene expression
How does quorum sensing work in gram-positive bacteria?
autoinducer binds to protein on cell surface, receptor becomes activated, initiating signalling
cascade, transcriptional regulator is activated, and DNA expression is altered
How does population density affect quorum sensing and virulence
CORRECT ANSWERS!!
How do bacterial cells divide?
binary fission - replication of chromosome, cellular growth, daughter cells are pinched off
replication begins before d-cells are pinched off
How do bacterial cells age?
senescence...
-inherit old cell material from "old" pole (side of cell wall inherited from parent cell)
-inherit damaged DNA
-inherit damaged proteins
-activation of damage defence systems instead of growth systems
Distinguish between the growth behaviours in microbes in response to oxygen.
obligate aerobe - aerobic respiration (O2 required)
facultative aerobe - oxygen very useful and not necessary
aerotolerant aerobe - strictly fermentative metabolism (tolerate O2)
strict anaerobe - oxygen is toxic, use fermentative metabolism or anaerobic respiration
microaerophile - require 2-10% O2 for growth... >20% is toxic
What are the types of reactive oxygen species?
superoxide anion, peroxide, hydrogen peroxide, hydroxyl radical, hydroxyl ion
How do bacteria utilize nutrients?
carbon - convert carbon to organic molecules, break down dead organic molecules (and release
carbon via respiration)
nitrogen - nitrifying bacteria oxidize nitrogen to produce energy
What are the metabolic groupings of organisms?
,energy sources (energy)
carbon sources (cell mass growth)
electron sources (energy conservation)
What distinguishes how organisms obtain energy?
chemotropic - obtain energy from external
chemicals (energy)
phototropic - obtain energy from light (energy)
What distinguishes how organisms obtain cell mass?
autotrophic - obtain carbon from CO2 (cell mass)
heterotrophic - obtain carbon from organic compounds (cell mass)
mixotrophs - hetero/auto
What distinguishes how organisms conserve energy in biochemical processes?
Lithotrophic - reduce from inorganics (energy conservation)
Organotrophics - reduce from organic compounds
What distinguishes the metabolic groups used to name microbes?
photoautotrophs - plants, algae and cyanobacteria
photoheterotrophs - green or purple non-sulphur bacteria, some archaea
chemoautotrophs - hydrogen/sulfur/nitrifying bacteria, some archaea
chemoheterotrophs -
aerobic: fungi, pathogenic bacteria
anaerobic: protozoa, bacteria, archaea
fermentation: bacteria, yeasts, archaea
How do bacteria utilize nutrients in anabolic processes?
need an energy source, a carbon source, an electron source
, How do bacteria utilize nutrients in catabolic processes?
breakdown materials to conserve energy, to produce energy or to create cell mass
Why must peptidogylcan layers undergo continuous remodelling and restructuring?
rigidity.... cell wall will lyse otherwise
What are important factors for the survival of bacteria?
ability to adapt to environmental conditions
communication with one another to coordinate their activites
How do persister cells resist antibiotics?
shift their metabolism to create enough ATP to remain viable, antibiotics have not targets, once
antibs are gone, shift back to division focused metabolism
How do bacteria use anabolic or catabolic processes to survive and adapt?
anabolics to grow and divide
catabolics to create enough energy to survive
How do bacteria use quorum sensing?
signal using autoinducers: n-acyl homoserine lactones, autoinducers 2, Com X
use signals to coordinate metabolic functions to adapt and survive (ie make biofilm)
How does quorum sensing work in gram-negative bacteria?
autoinducer is taken into cell, binds to intracellular receptor, receptor protein acts as a
transcriptional regulator by binding to DNA and altering gene expression
How does quorum sensing work in gram-positive bacteria?
autoinducer binds to protein on cell surface, receptor becomes activated, initiating signalling
cascade, transcriptional regulator is activated, and DNA expression is altered
How does population density affect quorum sensing and virulence
