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What are three prokaryotic traits?
- thick, complex outer envelope
- compact genome
- tightly coordinated cell functions
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What are the basic compenents of the bacterial cell?
- cytoplasm
- cell membrane
- cell wall
- nucleoid
- flagellum or other protrusions
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What are the chemical components common to all cells?
- water
- essential ions
- small organic molecules
- macromolecules
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What are the basic cell membrane components in bacteria?
- Hopanoids
- phospholipid bilayer
- tranporter proteins
- ATP synthase
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What is a phospholipid?
Glycerol with ester links to two fatty acids and a phosphoryl head group, with various side chains.
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Why can't cells stay in equilibrium?
ATP synthase is the main source of power for cells, and it requires a proton gradient to produce ATP
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What is selective transport?
cell membrane is semipermeable, so it is selective in that not everything can move in and out of the cell
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What is the different between passive and active transport?
Active transport requires energy, passive transport simply moves along the proton gradient.
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What are hopanoids?
Planar molecules filling in the gaps between hydrocarbon chains (phospholipids).
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What is the sacculus?
- The bacterial cell wall made up of PEPTIDOGLYCAN
- it provides shape, rigidity, and ability to withstand turgot pressue.
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What is the structure of murein or peptidoglycan?
- Long polymers of two disaccharides called NAG and NAM which make up the spiral backbone
- Peptides branch off of NAM (L, G, D, L, L)
- To form crosslink, a tetrapeptide is formed by dropping an L (Alanine), connects two NAMs
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What is D in the crosslinks?
- D is diaminopimelic acid, also called DAP
- it has a similar structure to LYSINE
- it is unique to peptidoglycan
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What is a beta linkage and where is it found in peptidoglycan?
- A beta linkage is used for support, where as an alpha linkage is for energy storage (such as in starch)\
- NAM and NAG are linked with thought a beta linkage
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How does penicillin work?
it blocks the formatino of the cross bridge/link
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All of the following are parts of peptidoglycan except:
A. N-acetyl muramic acid
B. Diaminopimelic acid
C. L-alanine
D.(alpha)- 1-4 glycosidic linkage
E. Peptide linkage
D because the 1-4 glycosidic linkage is a BETA linkage
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What are important characteristics of gram + bacteria?
- much thicker cell wall
- may have a slick capsule comprised of polysaccharides which prevent phagocitosis
- have teichoic acids for strength (specific to gm+)
- one membrane rather than two
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What is specific to mycobacteria and what are the implications?
- Gram+
- mycobacteria have MYCOLIC ACID, very unique.
- -mycolic acid can be targeted in antimicrobials to eliminate these bacteria
- they have a very complex cell envelope which requires a large amount of time and energy to produce, so they are slow growing.
- -This means is take far more time to eliminate these bacteria because antimicrobials generally target stages of GROWTH
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Which stain is used for Mycobacterium?
Acid fast
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Gram negative characteristics
outer membrane with toxic Lipopolysaccharides and transporter proteins/porin
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What are the three parts of LPS?
- Lipid A
- Core polysaccharide
- O polysaccharides
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Which part of LPS is toxic?
Lipid A
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Which part of LPS confers serotype specificity?
The O polysaccharides or O chains. Each one has different O polysaccharides; there can be multiple O chains in one species.
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What are several examples of gram positive bacteria?
Step, Staph, Bacillus
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What are several examples of gram negative bacteria?
Shigella, Salmonella, E. coli
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Which of the following is only found in Gram positive bacteria?
A. Peptidoglycan
B. Lipopolysaccaride (LPS)
C. Capsule
D. Teichoic Acid
Both C and D are exclusive to gram positive bacteria
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What color do gram negative bacteria turn with a gram stain and why?
It doesn't stain at all, because the thin cell membrane doesn't reatin the dye. It's then counterstained pink because the pink is a light enough color to not affect the darker staining of the gram positive bacteria.
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What color do gram positive bacteria turn with a gram stain and why?
purple because the thick cell wall retains the crystal-violet
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What is a nucleoid?
the region in prokaryotes that extends throughout the cytoplasm and holds the cell's genome
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What is a flagellum?
a spiral filament of protein monomers called flagellin. It's rotated by a proton motive force
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What is chemotaxis?
flagellum
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Capsule?
- slick outer coating that some bacteria have; made up of coat proteins.
- Prevents PHAGOCYTOSIS
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