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15 Cards in this Set
- Front
- Back
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What colour do gram pos/neg stain? |
Pos - thick peptidoglycan layer - stain purple Neg - thin peptidoglycan layer - stain pink |
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Name the two enzymes in peptidoglycan formation |
Transglycosylases act to connect the sugarsTranspeptidases act to create the peptidecross-bridges
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Name how 3 antibiotics work |
Bacitracin – stopsdephosphorylationof bactoprenol which shuttles precursor into the wall Vancomycin-binds D-Ala-D- Ala and stops crosslinking β-lactams inhibittranspeptidase reaction |
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What is the name of the enzyme which catalyses the transfer to outer leaflet? |
Flippases |
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What is gram negative outer membrane composed of? |
Lipopolysaccharide layer
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What is the S-layer? |
Surface layer In gram pos/neg Monomolecular layer composed of identical proteins or glycoproteins Gram positive – on peptidoglycan surface; Gram negative – adhered to outer membrane Helps protect from environmental stresses, predation and the immune response Self assembly |
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What is glycocalyx? Examples |
Extracellular polymers •Mostoftenin Gramnegativebut canbe Grampositive •Capsule– organisedand not easily removed.Used for adhesion •Capsulesallow production of biofilms eg. dentalplaque •Slimelayer– unorganisedand easilyremoved.Facilitates movement |
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What is a bacterial endospore? |
•Producedby some Gram-positivebacteria Stripped-down, dormant form to which the bacterium can reduce itself. Lack of nutrients •Stressresistant |
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Gram-pos component |
Lipoteichoic acid |
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Gram-neg component Function |
LPS - endotoxin O-antigen, outer core, inner core, lipid A •Vitalforcell viability,adhesion,bacteriophagerecognition |
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Fibrinogen |
Converted by thrombin into fibrin during blood clot formation |
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Which enzyme anchorsproteinsinthe Gram positivecell wallthrough theC-terminus |
SortaseA |
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•Type IV pili |
–Twitching motility, using pili as grappling hooks to pull the cell along |
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•Glidingmotility |
–Not well understood; either like twitching, or propelled by polar ejection of polysaccharide slime |
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Where are flagella located? |
Flagellamolecular motors areembeddedin the cellenvelope |
