bacteriology exam 1 questions with
complete solutions
how is the genome different in pro- v eu-karyotes - correct answer ✔✔prokaryotes: 1 chromo, may have
extrachromosomal DNA =plasmids
eukaryotes: mult chromosomes, extrachromasomal DNA = mitochondria
what is the structure of organelles in pro- v eu-karyotes - correct answer ✔✔pro: DO NOT have
membrane bound organelles in the cytoplasm
eu: do have membrane bound organelles --> nucleus, ER, golgi app
what are the basic external structures of a bacteria - correct answer ✔✔surface layers: S layer + capsule
appendages: flagella, pili, fimbriae
what are the boundaries of a bacteria - correct answer ✔✔-outer membrane
-cell wall
-cytoplasmic membrane
what is the fx of the cell wall - correct answer ✔✔maintains integretity of the cell (eg keeping osmotic
pressure in check)
*the only one that doesnt have this is mjicroplasma
what is the fx of the outer membrane - correct answer ✔✔-facilitates nutrient acquisition
-virulence
-protection
**some have, not all
,what is the fx of the cytoplasmic membrane - correct answer ✔✔(fragile, needs protection)
-controls nutrients coming in and out of the sytoplasm
-needs protection! this is why the cell wall is impt
what are the internal components of a bacteria - correct answer ✔✔-cytoplasm
-ribosomes
-inclusion
-nucleoid/chromosome
-cytoskeleton
-endospore
-plasmid
what is the main difference between gram pos and gram neg bacteria - correct answer ✔✔the
components of the cell wall (one can be decolorized and restained (neg), the other cant (pos)
what is the comp of the cell wall for a gram pos bacteria - correct answer ✔✔-they have a cell
membrane
-they have a large/thick peptidoglycan layer
-the surface proteins are on top of the peptidoglycan layer
-gives rigitiy and cell shape
-protects from osmotic challenge and some toxic compounds
what is the comp of the cell wall of a gram neg bacteria - correct answer ✔✔-cell membrane
-thin peptidoglycan layer
-lipoprotein layer
-outermembrane = lipopolysaccharide (LPS) with surface proteins in it)
-can have porins --> allow molecules into the cell (hydrophilic) and eject molecules out
,*uses the other membrane (LPS) for protection
what are the 2 main shapes of bacteria? - correct answer ✔✔rods and cocci (spherical)
-generally 1-10um in length and 0.2-1 um in width
-but they can come in many shapes and sizes
how do we commonly group bacteria? - correct answer ✔✔using gram status and shape
-gram pos rods
-gram pos cocci
-gram neg rods
*dont really see gram neg cocci in vet med but are mucosal flora
what are different examples of bacterial attachement - correct answer ✔✔-fimbriae
-biofilm
-capsule
what is fimbriae - correct answer ✔✔-protein structures on the outside of the cell
-fine, harilike that faciliate adhesion through "grappling hook-like" mechanism
-usually distributed all over the cell surface
-can aid in ID
*amino acid comp of the proteins may be changed in oder to evade immune syst (good target Ag for
immune cells)
what is biofilm - correct answer ✔✔-aggregate of bacteria and extracellular components
-forming complex comminites, often a single spp but not always
, -helps bacteria survive in adverse conditions (decreases immune response, anti microbial drugs are
unable to penetrate through matrix well)
*occurs on implants and invasive devices, in tussues
what is a capsule - correct answer ✔✔in addition to a cell wall, they can have a layer external to cell wall
with mult functions. usually comp of polysaccharides and tightly bound to the cell wall)
-avoid phagocytosis
-resistance to toxic substances
-adherence
what is the S layer - correct answer ✔✔the "slime layer"
-less robust than the capsule
-monolayer of protein used for protection and attachment
-loose structure and loosely adhered to cell (can wash away, but still helpful for protection and
attachment)
what are types of tools do bacteria use to move - correct answer ✔✔-flagella
what is flagella - correct answer ✔✔-long round filaments embedded into cell wall (change direction
with change in rotation
-facilitates spread in response to chemotactic signals (with in environment)
-can be used to ID bact
what are bacterial mechanisms of DNA exchange - correct answer ✔✔-conjugation
-tranformation
-transduction
what is pilus - correct answer ✔✔-mechanism for bacterial cell to cell sharing of chromosomal or
plasmid DNA called conjugation
complete solutions
how is the genome different in pro- v eu-karyotes - correct answer ✔✔prokaryotes: 1 chromo, may have
extrachromosomal DNA =plasmids
eukaryotes: mult chromosomes, extrachromasomal DNA = mitochondria
what is the structure of organelles in pro- v eu-karyotes - correct answer ✔✔pro: DO NOT have
membrane bound organelles in the cytoplasm
eu: do have membrane bound organelles --> nucleus, ER, golgi app
what are the basic external structures of a bacteria - correct answer ✔✔surface layers: S layer + capsule
appendages: flagella, pili, fimbriae
what are the boundaries of a bacteria - correct answer ✔✔-outer membrane
-cell wall
-cytoplasmic membrane
what is the fx of the cell wall - correct answer ✔✔maintains integretity of the cell (eg keeping osmotic
pressure in check)
*the only one that doesnt have this is mjicroplasma
what is the fx of the outer membrane - correct answer ✔✔-facilitates nutrient acquisition
-virulence
-protection
**some have, not all
,what is the fx of the cytoplasmic membrane - correct answer ✔✔(fragile, needs protection)
-controls nutrients coming in and out of the sytoplasm
-needs protection! this is why the cell wall is impt
what are the internal components of a bacteria - correct answer ✔✔-cytoplasm
-ribosomes
-inclusion
-nucleoid/chromosome
-cytoskeleton
-endospore
-plasmid
what is the main difference between gram pos and gram neg bacteria - correct answer ✔✔the
components of the cell wall (one can be decolorized and restained (neg), the other cant (pos)
what is the comp of the cell wall for a gram pos bacteria - correct answer ✔✔-they have a cell
membrane
-they have a large/thick peptidoglycan layer
-the surface proteins are on top of the peptidoglycan layer
-gives rigitiy and cell shape
-protects from osmotic challenge and some toxic compounds
what is the comp of the cell wall of a gram neg bacteria - correct answer ✔✔-cell membrane
-thin peptidoglycan layer
-lipoprotein layer
-outermembrane = lipopolysaccharide (LPS) with surface proteins in it)
-can have porins --> allow molecules into the cell (hydrophilic) and eject molecules out
,*uses the other membrane (LPS) for protection
what are the 2 main shapes of bacteria? - correct answer ✔✔rods and cocci (spherical)
-generally 1-10um in length and 0.2-1 um in width
-but they can come in many shapes and sizes
how do we commonly group bacteria? - correct answer ✔✔using gram status and shape
-gram pos rods
-gram pos cocci
-gram neg rods
*dont really see gram neg cocci in vet med but are mucosal flora
what are different examples of bacterial attachement - correct answer ✔✔-fimbriae
-biofilm
-capsule
what is fimbriae - correct answer ✔✔-protein structures on the outside of the cell
-fine, harilike that faciliate adhesion through "grappling hook-like" mechanism
-usually distributed all over the cell surface
-can aid in ID
*amino acid comp of the proteins may be changed in oder to evade immune syst (good target Ag for
immune cells)
what is biofilm - correct answer ✔✔-aggregate of bacteria and extracellular components
-forming complex comminites, often a single spp but not always
, -helps bacteria survive in adverse conditions (decreases immune response, anti microbial drugs are
unable to penetrate through matrix well)
*occurs on implants and invasive devices, in tussues
what is a capsule - correct answer ✔✔in addition to a cell wall, they can have a layer external to cell wall
with mult functions. usually comp of polysaccharides and tightly bound to the cell wall)
-avoid phagocytosis
-resistance to toxic substances
-adherence
what is the S layer - correct answer ✔✔the "slime layer"
-less robust than the capsule
-monolayer of protein used for protection and attachment
-loose structure and loosely adhered to cell (can wash away, but still helpful for protection and
attachment)
what are types of tools do bacteria use to move - correct answer ✔✔-flagella
what is flagella - correct answer ✔✔-long round filaments embedded into cell wall (change direction
with change in rotation
-facilitates spread in response to chemotactic signals (with in environment)
-can be used to ID bact
what are bacterial mechanisms of DNA exchange - correct answer ✔✔-conjugation
-tranformation
-transduction
what is pilus - correct answer ✔✔-mechanism for bacterial cell to cell sharing of chromosomal or
plasmid DNA called conjugation
