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29 Cards in this Set
- Front
- Back
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What is the cytoplasmic membrane made of?
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phospholipid bilayer, variety of groups attached to glycerol backbone
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Integral membrane proteins vs. peripheral membrane proteins?
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integral-all embedded in membrane
Peripheral-one portion anchored in membrane |
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What are the functions of membrane proteins?
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Transport molecules in and out, energy-transformation, motility, sensing the env
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What are sterols?
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found in eukaryotic membranes, not in bacteria, strengthen and stabilize membranes
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What are hopanoids?
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structure similar to sterols, membranes of bacteria
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Archaeal membrane vs. bacteria/eukarya membrane?
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Archaea-Ether linkage in phospholipid
lack fatty acids, isoprene's instead lipid monolayer/bilayer/mixture Bacteria/Eukarya-Ester linkage |
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What are the 3 major classes of transport system in prokaryotes?
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simple transport
group translocation ABC system |
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3 transport events-
1) Uniporter |
transport in one direction across membrane, goes down conc. gradient
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3 transport events-
2)Symporter |
Co-transporter, actively transports target molecule
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3 transport events-
3) Antiporter |
transport molecule across membrane while also transporting another in opp. direction.active transport
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Describe ATP Binding Cassete (ABC) transport system
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usually involved in uptake of organic compounds
high substrate specificity periplasmic binding proteins |
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What are functions of translocases?
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export proteins through and inserting into prokaryotic membranes
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What is the sec translocase system?
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exports proteins and inserts integral membrane proteins into membrane "secretion"
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What is the type 3 secretion system?
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common in pathogenic bacteria
secreted protein translocated directly into host |
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What is the major part of the cell wall of bacteria?
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Peptidoglycan-composed of polysaccharide (M&G sugars, crosslinked peptides attached to sugars)
Attacked by lysozyme |
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Gram + bacteria structure?
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up to 90% peptidoglycan, often have teichoic acids in cell wall
Lipoteichoic acids covalently bound to membrane lipids-anchor cell wall to membrane |
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Gram - bacteria structure?
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10% peptidoglycan, most cell wall composed of outer membrane (lipopolysaccharide layer)
endotoxin |
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What does the LPS layer consist of?
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core polysaccharide and O-polysaccharide, replaces most phospholipds in outer half of outer membrane
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What is the periplasm?
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space located between cytoplasmic and outer membrane
Contains many proteins |
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What are the functions of capsules and slime layers?
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polysaccharide layers that:
-assist in attachment to surfaces -protect against immune system and phagocytosis -resist desiccation (prevent drying out) |
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What is the function of fimbriae
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-filamentous protein structures that enable organisms to stick to surfaces or form pellicles.
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What are pellicles?
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ayer of cells formed by the fimbriae of bacteria on liquids and help bacteria stick together (so they don't get washed away)
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What is the function of pili?
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filamentous protein structure (longer than fimbriae), assist in surface attachment, conjugation(genetic exchange between cells), twitching motility (Type IV Pili)
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What are examples of carbon storage polymers?
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Poly-B-hydroxybutyric acid (PHB)= lipid
Glycogen=glucose polymer |
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What are magnetosomes?
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magnetic storage inclusions.
Contains Fe to detect earth's magnetic filed, bacteria can known up & down to get more O2 |
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What are gas vesicles?
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Help with buoyancy in planktonic cells, impervious to water
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What are endospores?
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Highly differentiated cells resistant to heat, chemicals, lysozyme and radiation
Onl present in some Gram+ bacteria |
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What is the structure of an endospore?
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Complex: Exosporium, spore coat, core wall, cortex, DNA
Core contains small acid-soluble proteins (SASP) to protect DNA genome |
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What is the dormant stage of a bacterial life cycle?
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Endospore
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