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30 Cards in this Set

  • Front
  • Back
the cell envelope of bacteria contains what?
cell wall, cell membrane, capsule, pili, and flagella
how do archaea relate to humans and what distinguishes them biochemically from bacteria?
some species are present in the digestive tract. They have no peptidoglycan and different membrane chemistry
the 4 bacterial groups that are pathogenic are...?
gram +, gram -, spriochetes, and chlamydia
of the organelles that all eukaryotic cells contain, which are not present in bacteria?
nucleus (and associated parts), ER, golgi, and mito
how many proteins are found in the bacterial RNA polymerase? eukaryotic RNA poly?
one. three
branched filamentous bacteria resemble what?
fungi
bacilli can form what secondary characteristics?
diplo, strep, and cocco (sphere like rod)
mucoid colony appearance usually indicates what? waxy? thin and spread out? pigment?
capsules. high lipid content possibly mycobacterium. high motility. protection against light thus not usually pathogenic
compare gram pos with gram neg
gram pos have thick peptigoglycan outer layer then membrane. gram neg have outer membrane of LPS then a periplasmic layer with a thin layer of peptidoglycan within it and then the cell membrane
what proteins that can be possible virulence factors are found in the peptidoglycan layer of gram pos bacs?
teichoic and lipoteichoic acids
what is the significance of the periplasmic space in gram neg bacs?
there may be virulence factors
describe the color and results of a gram stain and what are some exceptions thatr make this test inaccurate?
purple is pos while red is negative. dead or damaged orgs will stain red. orgs lacking peptidoglycan or mycobacteria with a waxy coating have inaccurate results
what are the membrane lipids found in the bacterial cell membrane?
PE, PG, cardiolipin, and sterols (ONLY in helicobacter and mycoplasmas)
the chief role of the peptidoglycan layer in bacs is for what? what is its role in pathogenesis?
resistance to osmotic stress. it has pyrogenic activity
describe the chemical structure of peptidoglycan. what enzyme can disrupt it and how?
repeating monomers of NAG and NAM connected by a B 1,4 link with a sugar backbone and peptide crosslinks. lysozyme disrupts the B 1,4 links.
what two compounds in the chemical structure of peptidoglycan are never found in eukaryotes?
NAM and DAP
describe the structure and function of the LPS of gram negs.
o specefic polysaccharide then core polysaccharide then the toxic lipid A. the oliogosaccharide side chain produces virulence. the core provides resistance to hydrophobic compounds. the outer LPS membrane prevents large compounds from entering. Divalent calcium and magnesium strengthen the LPS, but it is weakend by EDTA. It is toxic to humans. The extensive external size of the LPS reduces the interaction of external compounds to the lipid bilayer
what does the LPS do to humans?
activates B cells, stimulates macs and dendritic cells to produce inflammatory cytokines, causes early leukopenia, enhances glycolysis thus may lead to hypoglycemia.
shock due to LPS or other septic symptoms can be fatal how? what does the activation of the coagulation pathway by cytokines lead to?
extreme hypotension caused by vasodilation via NO from the cytokines leads to multiorgan failure due to hypoperfusion. disseminated intravascular coagulation
describe the envelope of mycobacteria (includes TB)?
related to gram pos, but do not stain pos, have outer layer of mycolic acid which is a lipid like, waxy substance. This provides resistance to detergents, many antibiotics and other antibacterial agents. It will stain acid fast
describe the envelope of mycoplasmas.
no cell wall, one membrane with sterols, again related to gram pos
what does compliment do to gram neg bacs? gram pos bacs?
lyses the bac. opsonizes but does not lyse
what are the structure, function, and alternative names for the capsule?
usually layer of polysaccharides (polypeptide in B. anthracis). It is an important virulence factor via antipahgocytic activity, adherance ability, and partial inhibition of complement mediated lysis.
what organisms is vaccination with their capsular material effective?
H. influenzae type b and S. pneumoniae.
another name for the antigenic aspect of flagella is...?
H antigen
describe the structure, function, and uses of the pili.
composed of protein subunits, cover entire cell surface, specialized sex pili transfer plasmids during conjugation. promote adherence to host or other bacteria. and they are antigenic.
what kind of bacteria can produce endospores?
some gram + bacteria
endospores are only sensitive to what?
steam (autoclave), glutaraldehyde, hypochlorite, and peracetic acid
describe the structure of the endospore and the specefic function of the different levels of structure.
the core contains the genome, protein synth machinery, and energy. Next is the spore wall which is made of peptidoglycan, then is the cortex which is concentric layers of peptidoglycan, then the spore coat which is keratin like and contains ample disulfide bonds, then the exosporum which is the remnant of the mother cell membranes. note that dipicolinic acid is found in all endospores and helps protect DNA
the oxidase test detects what? what orgs does it help differentiate?
detects the presence of cytochrome C oxidase and differentiates pseudomonads from enterobacterciae.