Introduction to Bacteriology Flashcards
Which archaea are pathogenic?
None
What distinguishes prokaryotes from eukaryotes?
A nuclear membrane
What are bacterial capsules (glycocalyx) usually made of, what do they do and what else are they called?
Usually made of polysaccharide (may be proteinaceous), help bacteria survive in host (aka virulence factors)
What do bacterial fimbria do?
Help colonize host by aiding in attachment
What do bacterial pili do?
Aid in genetic exchange
What makes prokaryotic ribosomes different from eukaryotic ribosomes?
They are smaller (70S, containing 50S and 30S subunits) than eukaryotic ones (80S)
What staining method is used to visualize mycobacteria?
Acid-fast staining
What are the terms for bacteria with a spherical shape and rod-like shape respectively?
Coccus (e.g. streptococcus) and bacillus (e.g. escherichia coli)
What are the terms for S shaped bacteria shorter than one sine wave and longer than one sine wave respectively
Shorter - spirillum (e.g. helicobacter), longer - spirochetes (e.g. borrelia)
4 types of flagellar arrangements on bacteria
Monotrichous (single, polar), Amphitrichous (a tuft at each end), Lophotrichous (one or more at each pole), Peritrichous (distributed over entire surface)
What type of organisms does acid fast stain stain for?
Those with high lipid content (often used with hard to stain organisms)
What does India Ink stain for?
It is a negative stain for capsules
Sporulation
Reversible differentiation in response to conditions. Conversion to dormant state when nutrient depleted. Done by some gram-positive bacteria, esp Bacillus and Clostridium genera
Three basic parts of a flagellum
Filament (made of flagellin), Hook, Basal body
What is another name for flagellar protein and why is it called this?
H antigen. It is highly antigenic and useful for distinguishing different Gram-negative baceteria
Axial filaments (endoflagella)
Bundles of filaments similar to flagella but under a sheath. Used by spirochetes
What about their composition differentiates prokaryotic PMs from eukaryotic PMs?
Prokaryotic plasma membranes contain no sterols, they are much more fluid as a result
What is the major component of bacterial cell walls, what other organisms is it found in, and what is it composed of?
Peptidoglycan. Unique to bacteria. Comprise of N-acetyl glucosamine (NAG) and N-acetyl muramic acid (NAM)
What type of bond joins NAM and NAG in bacterial walls?
B1-4 glycosidic bond
What is the difference in the composition of cell wall between gram-negative and gram-positive?
Gram-negative contain diamino pimelic acid (DAP), gram-positive contain diamino AA lysine instead of DAP
What type of bacteria have a peptide bridge in their cell walls?
Gram-positive bacteria have a variable length peptide bridge in their cell walls (gram negative have direct peptide bonds linking peptidoglycan)
What type of bacteria have extensively cross-linked cell walls?
Gram-positive bacteria. Gram-negative cells have a thin layer of peptidoglycan, while gram-positives have multiple cross-linked layers
What bacterial function do vancomycin, penicillins, and bacitracin inhibit?
Cell wall (peptidoglycan) synthesis. Vancomycin (binds terminal alanine) and penicillins (inhibits PBPs that remove terminal alanine) prevent cross-linkage, bacitracin blocks dephosphorylation of bactoprenol-PP
What type of bacteria have teichoic acids in their cell wall and what is the sigificance of these molecules?
Gram-positive bacteria. Teichoic acis and lipoteichoic acids are major antigenic determinants
