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34 Cards in this Set
- Front
- Back
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How do prokaryote and eukaryotes differ in nucleus and membrane?
Chromosome? Organelles? |
- no true nucleus/no nuclear membrane vs Possess discrete nucleus surrounded by membrane.
- Single chromosome vs. Multiple chromosomes/mitotic apparatus - No membrane bound organelles vs. Membrane bound organelles |
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Characterize bacterial chromosome
What are plasmids? |
- single, circular ds DNA, no histones, no nuclear membrane-transcription and translation are coupled
- smaller, non-essential circular ds DNAs that can encode antibiotic resistance and virulence determinants |
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- coiled cytoplasmic membrane that acts as an anchor to bind and pull apart daughter chromsomes during cell division
- Gram pos |
What is a mesosome?
What is the type of bacteria that contains mesosome, gram pos or neg? |
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What is eukaryotic ribosomes made of?
What is prokaryotic ribosomes made of? |
- 60S+40S = 80S
- 50S+30S = 70S |
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What is prokaryotic cytoplasmic membrane made of?
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- Lipid bilayer, but lacks steroids (e.g. cholesterol)
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What are the three different shapes that the bacterial cell walls can form?
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- Spherical (cocci), rod-shaped, spiral
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Which type of bacteria, gram pos or neg, has a peptidoglycan cell wall layer?
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- Gram pos
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What is the process of gram staining?
Explain results. |
- fixation -> stain crystal violet -> iodine tx -> unbound and excess stain is removed by washing with decolorizer -> red counterstain safranin
- gram + remains purple because stain gets trapped in a thick, cross-linked peptidoglycan. Gram - turns red because the thin peptidoglycan layer causes the stain to leak |
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Compare gram pos and gram neg bacterial cell walls.
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- gram pos has thick peptidoglycan layers that contains teichoic and lipoteichoic acids
- gram neg has thin peptidoglycan layer and outer memb that has LPS, PL, and ptns. |
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What is the cross-linking bond that forms peptidoglycan?
Why is this link important? |
- D-alanine - D-alanine dipeptide
- b/c it is the basis for action of beta-lactam and vancomycin antibiotics |
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What is cell wall biosynthesis catalyzed by?
What do penicillins resemble? What will binding of penicillin do? |
- transpeptidases, carboxypeptidases and endopeptidases = “penicillin binding proteins” creates a septum for cell division
- the transition state conformation of D-ala-D-ala units bound to these enzymes - inhibit synthesis of peptidoglycan -> cell death |
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What is the function of autolysins (e.g. lysozyme)?
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- determine cell shape
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What type of bacteria will you find LPS/Endotoxin?
Function of LPS/Endotoxin? What is the structure of LPS? |
- Gram Negative
- activates B cells -> release of proinflammatory cytokines -> fever and shock - O-antigen: 4-7 sugars repeated 50-100X; Core: 9-12 sugars, including KDO (3-deoxy-D-manno-octulosonic acid); Lipid A: disaccharide of -1,6-D-glucosamine with long chain fatty acids; attaches to KDO of the core |
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Which type of bacteria contains spores?
When will sporulation occur? What is sporulation? What is a spore? |
- Gram positive -NEVER gram negative
- under harsh environmental conditions - process by which a vegetative cell converts to a dormant, metabolically inactive state - dehydrated, multi-shelled structure that protects the bacterium |
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What are capsules on bacteria?
Function as barrier? Phagocytosis? Immunity? |
- loose carbohydrate or protein layers on the surface of Gram positive or Gram negative organisms
- provide a physical barrier between environment and bacterial cell - inhibit phagocytosis through multiple mechanisms including interfering with complement deposition - mediate immune evasion through molecular mimicry to host glycans |
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Function of bacterial flagella?
Serotype of flagella? |
- Provide motility to allow the bacterial cell to swim toward nutrients and away from poisons
- serodeterminants (H serotyping scheme) |
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What is the type of bacteria, gram pos or neg, that has pili?
What is bacterial pili or fimbriae? Function? |
- Gram neg
- hairlike structures on surface - promote bacterial aggregation, microcolony formation, subsequent invasion and biofilm formation |
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What part of pili allows binding to bladder and kidney cells?
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- Tip protein called adhesin
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What forms the basis for serological typing schemes of bacteria?
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- Surface antigens
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What is serotype for LPS?
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- “O”
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What is serotype for flagellar
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- “H”
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What is serotype for capsular
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- “K”
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What type of bacteria has an outer membrane, gram pos or neg?
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- Gram neg
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What type of bacteria has a thicker cell wall, gram pos or neg?
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- Gram pos
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What type of bacteria has LPS, gram pos or neg?
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- Gram pos
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What type of bacteria has endotoxin, gram pos or neg?
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- Gram neg
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What type of bacteria has teichoic acid, gram pos or neg?
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- Gram pos
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What type of bacteria undergoes sporulation, gram pos or neg?
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- Gram pos
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What type of bacteria has a capsule, gram pos or neg?
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- Both
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What type of bacteria is lysosome sensitive?
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- Gram pos
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What type of bacteria is penicillin sensitive?
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- Gram pos
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What is bacterial biofilm?
Function? What are biofilms resistant to? |
- structured community of bacterial cells enclosed in a self-produced polymeric matrix and adherent to an inert or living surface.
- A protected mode of growth that allows survival in a hostile environment. - Resistant to host defenses and antibiotics |
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Where are biofilms isolated in hospitals?
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- medical devices (catheters, valves, prosthesis)
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What are human infections involving biofilms?
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Periodontitis
Cystic Fibrosis Chronic Bacterial Prostatitis Otitis Media Native Valve Endocarditis |
