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27 Cards in this Set
- Front
- Back
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Difference between Gram- and Gram+ bacteria
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Gram+ has Teichoic acid
Gram+ has multilayed peptidoglycan Gram- has a monolayer |
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Which type of bacteria has more peptidoglycan in their cell wall - Gram - or Gram+
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Gram+
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Which type of bacteria has teichoic acid in their cell wall?
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Gram+
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Teichoic acid
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Found in the cell wall of Gram+ bacteria embedded in the peptidoglycan
Plays an antigenic role and role in adherence of the cell as well as gives the cell wall a negative charge Made up of monomers of glycerol/ribitol and phosphate Two types Wall teichoic acid Lipoteicoic acid |
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Lipoteichoic acid
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Type of Teichoic acid found in Gram+ peptidoglycan cell wall
Always made up of Ribitol and Phosphate (no glycerol) Linked and embedded in the cell membrane itself Lipid portion is embedded in the cell membrane |
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Virulence factor
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Anything that helps microbes stick to our cells
For example: Teichoic acid or pili |
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Antigenic role of Teichoic acid
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Teichoic acid elicits an antibody response in our body
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Gram- cell wall components
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Lipopolysaccharide (LPS)
Porins Lipoprotein Periplasm Binding proteins Monolayer of Peptidoglycan |
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What percentage of the cell is peptidoglycan in Gram+ and Gram- cells
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Gram+ - 80%
Gram- - 10-15% |
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Where is the peptidoglycan layer found in Gram- bacteria?
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In the periplasm
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Endotoxin
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The lipopolysaccharide layer in the outer membrane of Gram- bacteria
Composed of: Core polysaccharide that is marker for presence of Gram- bacteria O-antigen that has 25 repeating subunits of 3-5 sugars used to differentiate Gram- Lipid-A - what causes toxicity to us |
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O antigen
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25 repeating subunits of 3-5 sugars
Stick up from the surface of bacterial cells Used to differential Gram- bacteria because of Multiple variations in sugar combination Immune system can recognize all these different O antigens and destroy them when recognized |
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Lipid A
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Component of LPS in Gram- bacteria
This is what causes toxicity to us and elicits a fever triggered in the hypothalamus |
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What bacterial cells have defects in their cell walls?
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Protoplasts
Spheroplasts L-forms Mycoplasma |
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Protoplasts
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Gram+ bacteria treated with Lysozyme
Lost all the PTG in their cell walls Therefore no strength and rigidity to their cell walls They eventually lyse and dye |
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Spheroplasts
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Gram- bacteria treated by lysozyme
Lost all PTG in their periplasmic space Still able to survive b/c additional outer cell membrane offers a sort of back-up protection |
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L-forms
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Protoplasts and Spheroplasts that can still survive and reproduce without cell walls
Done by hiding out in tissues that have osmotic pressure equal to their cytoplasm They are immune to penicillin because they no longer have a cell wall for it to act on |
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Mycoplasma
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The only bacterial cell that does not have a cell wall genetically
Instead have sterols in their cell membrans to provide strength and rigidity |
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Capsule
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Extracellular slime layer
Not essential to the life of bacteria but offers additional benefits Made up of polysaccharides giving slimy texture Prevents phagocytosis by macrophages Prevents dessication of cell Enhances adherence Ex: Glycocalyx in Strep mutans |
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What are the components of Bacillus Anthracis's Capsule
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Instead of polysaccharides it is made up of D-Glutamic acid
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Glycocalyx
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Capsule of Strep mutans
Composed of polysaccharides Prevents phagocytosis, dessication and helps in adherence |
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Why does it take all bacterial species 40min to replicate its entire genome but only 20 mins of generation time to double its population?
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Because a 2nd round of replication can begin even before the 1st round is complete
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DNA Gyrase
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An enzyme that coils and uncoils DNA during replication that is necessary for binary fission
Inhibited by Cipro |
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Cipro
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Antibiotic that targets and inhibits the action of bacterial DNA Gyrase
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Prokaryotic Ribosome
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70S ribosome with 50S and 30S subunits
This size is different from eukaryotic cells therefore antibiotics can target this without harming our cells |
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Eukaryotic Ribosome
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80S ribosome with 60S and 40S subunits
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Inclusions
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Organic and Inorganic types
Storage granules Organic: Lipid granules store lipids as polymers of beta-hydroxybuteryic acid Sugar granules store sugar as granulose inclusion boies Inorganic: Volutin store phosphate for DNA and RNA synthesis |
