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22 Cards in this Set
- Front
- Back
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prokaryotes
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external appendages
-flagella -pili -fimbria glycocalyx -capsule, slime layer cell envelope -(outer membrane) -cell wall -cell membrane internal -cytoplasm -ribosomes inclusions -nucleoid/chromosome -actin cytoskelton -endospore |
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main difference from prokaroyotes and eukaryotes
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prokaryotes have no nucleus!
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prokaryotic cell
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refer to chapter 4 slide 4
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the nucleoid
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-contains the genetic material of prokaryote
-no nuclear membrane -single circular chromosome (haploid) -plasmids may be present -the DNA is in close proximity to the cytoplasm and ribosomes |
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the cytoplasm
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-contains the DNA in the nucleoid
-many soluble proteins are present -carbs and other intermediates are abundant -this is the site of nearly all chemical reactions -bacteria have a cytoskeleton, but is operates differently than in eukaryotes--in prokaryotes it anchors things -inclusion bodies may be present **you want things to float in place in cytoplasm--neutral buoyancy |
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cytoplasmic membrane
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-phospholipid bilayer
-hydrophobic proteins -phosphatidylcholine -semi-fluid nature *proteins act as transports |
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bacterial cell walls
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-provide structure and shape and protect cell from osmotic forces
-assist in some cells in attaching to other cells or in resisting antimicrobial drugs -can target cell wall of bacteria with antibiotics -give bacterial cells characteristic shapes 1. peptides are small chains of amino acids (proteins) 2. glycan are sugar -composed of peptidoglycan -scientist describe two basic types of bacterial cell walls: gram positive and gram negative *set in shape, bacterial cell will just fill in |
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peptidoglycan cell wall
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-sugar backbone
-protein side-chain -present in most bacteria -provides strength -glycan chains are stable (forms layers) refer to pictures from slides 9 and 11 |
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peptidoglycan structure
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disaccharide
-NAG -NAM peptide chain -D-amino acids |
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gram positve
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-thick peptidoglycan
-teichoic acid -lipoteichoic acid -one membrane (periplasm) -can't move up or down side to side of front to back -lipo to lipid; will anchor to cell and membrane together |
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gram negative
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-two membranes
-lipopolysaccharide -porins -thin peptidoglycan -periplasm refer to chapter 4 slides 11 and 12 pictures |
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lipopolysaccharide
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outer layer of the outer membrane
three domains 1. lipid A (endotoxin) 2. core polysaccharide 3. O Antigern -O antigen is the dominant antigen of gram negative cells--can kill you (bloody E. Coli) |
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acid fast bacteria
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-mycobacteria contain mycolic acid (a wax)
-modified gram-positive structure -includes important pathogens 1. tuberculosis 2. leprosy 3. M. avium 4. opportunisitc would infections *wax allows them to keep shape |
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prokaryotic appendages
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fimbria: used for attachment and sometimes motility
pili: used for attachment and genetic exchange--are hollow and help share info. |
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flagellum structure
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-bacterial locomotior
-electric motor -dozens of proteins -rotates rapidly -propels the cell thru its environment |
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flagella of spirochetes
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-axial filaments
-flagella are located in the pereplasm -cause the bacterium to corkscrew -can move through viscous media |
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bacterial motility
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-depends upon differential application of force over time
--spin direction --spin duration --tumbles --runs *looking for sugar up and down gradients following signals |
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capsule of glycocalyx
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-commonly polysaccharides (carbohydrates)
--a few are polypeptides -used to avoid phagocytosis -these are usually important for pathogenisis |
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mycoplasma
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-true bacteria
-very small in size -no peptidoglycan wall -variable in shape -may have cytoskeleton -are important pathogens -contain cholesterol in membranes but don't make it themselves |
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bacterial shapes
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refer to slides in chapter four and learn!
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bacterial L-forms
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-spheorplasts or protoplasts: lose their cell walls (protoplasts)
-naturally forming -spontaneously form during growth -can occur under stress conditions during infections |
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endospore formation
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review from chapter four on slides
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