Term
| 7 differences btwn pro & eukaryotic cells |
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Definition
1. Prokaryotic cells lack true nucleus
2. Prokaryotic cells lack true membrane bound organelles
3. Prokaryotes usually have a single, linear or circular chromosome as opposed to eukaryotes' 23
4. Plasmids are common in prokaryotes, rare in eukaryotes
5. Ribosomes are smaller in prokaryotes
6. Flagella smaller; one protein fiber in prokaryotes
7. Prokaryotes cells have gas vesicles, none observed in eukaryotes |
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Term
| Prokaryotic cell membrane functions |
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Definition
-selective permeable barrier
-separation of cell from its environment
-location of crucial metabolic processes (like photosynthesis)
-detection of and response to chemicals in surroundings w/aid of receptor molecules |
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Term
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Definition
A lipid is a naturally occurring, mostly hydrophobic, storage and and structural molecules in pro&eukaryotic cells (fats, oils, waxes, cholesterol...)
NOT ALL LIPIDS DERIVED FROM FATTY ACIDS |
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Term
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Definition
| A carboxylic acid with a hydrocarbon chain and a terminal carboxyl group |
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Term
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Definition
| Composed of mono, di,and tri-substituted glycerols |
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Term
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Definition
| A lipid with a carbohydrate attached. Main function to provide E and serve as markers for cellular recognition. |
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Term
| Asymmetry of most membrane lipids |
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Definition
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Term
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Definition
-Interact with water (usually phosphorylated ethanol amine)
-Hydrophilic |
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Term
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Definition
-Insoluble in water
-Hydrophobic
-Glycerol esters of long chain fatty acids |
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Term
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Definition
| Hapnoids: cholesterol and bacteriohopenetetrol (a hoponoid mainly to strengthen membrane) |
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Term
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Definition
| Loosely associated with the membrane and easily removed |
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Term
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Definition
Embedded within the membrane and not easily removed
eg. secretion system/transporter |
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Term
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Definition
A highly organized structure that is also asymmetric, flexible, and dynamic
Non polar tail is ester-linked glycerolipid acids |
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Term
| Internal membranous structures |
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Definition
-Plasma membrane infoldings
-observed in many photosynthetic bacteria and in prokaryotes with high respiratory activity |
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Term
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Definition
| Amphipathic lipids arranged in a bilayer (similar to bacteria) |
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Term
| Polar head of archaeal lipids: |
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Definition
| variable structures (phosphate, sulfur, and sugar containing groups) |
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Term
| Nonpolar tail of archaeal lipids are linked how? |
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Definition
-They are ether linked glycerolipid hydrocarbons (pg. phytanol)
-Non acid tails
-Stronger structure- more rigid. Low pH environments, high temp... EXTREME conditions |
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Term
| Additional nonpolar lipids in archaea |
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Definition
Squalene
Tetrahydrosqualene |
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Term
| Amphipathic lipids in Archaea sometimes dimerize (fuze together), form a lipid monolayer plasma membrane. Why? |
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Definition
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Term
| Diff. between Archaeal membrane lipids |
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Definition
Amphipathic lipids:
POLAR HEAD: Phosphorylated ethanolamine in Bacteria, variable in Archaea
NONPOLAR TAIL: Glycerol ESTER of various fatty acids in BACTERIA
Glycerol ETHER of C20 hydrocarbons in Archaea
*Nonpolar tail can dimerize to form a membrane monolayer in some archaea
*Additional nonpolar lipids are present in Archaea- Squalene, tetrahydrosqualene
Bacteria- hopanoids |
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Term
CYTOSKELETON
3 groups, what they are identified in (bacteria/archaea) |
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Definition
-Actin: forms microfilaments
-Tubulin: forms microtubules
-Lamin, Keratin and other proteins: intermendiate filaments
*Homologs of all 3 eukaryotic cytoskeletal elements have been identified in bacteria and 2 in archaea
*Unique becterial cytoskeleton proteins identified as well
*functions are similar as in eukaryotes
-role in cell division, protein localization, and determination of cell shape |
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Term
| 3 best studied examples of cytoskeleton |
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Definition
*FtsZ- (Zipper) Many bacteria and archaea
-Forms ring during septum formation in cell division (tubulin analogue)
*MreB- many rod shaped bacteria, some archaea
-Maintains shape by positioning peptidoglycan syntheis machinery (actin homologue)
-CreS- (C for CURVE) Rare, maintains curve shape (lamin and keratin homologue)
-from caulobacter bacteria |
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Term
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Definition
*Granules of in/organic material that are stockpiled by the cell for future use (storage inclusions)
*Granules of enzymes, structures, or specific chemicals that are required for proper cell functions (non storage inclusions; these chemicals are not really food) |
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Term
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Definition
Inorganic and organic
*storage of nutrients, metabolic end products, E, building blocks |
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Term
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Definition
*Glycogen
-Glucose polymer
-Formed when bacteria is in a carbon rich environment that is lacking in another essential nutrient (N,S,P...)
*Poly B-Hydroxybutyrate (or PHB)
-Polymers of a hydroxy fatty acid
-Interest in utilization for plastics |
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Term
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Definition
-Polymer
-Large polypeptides containing about equal quantities of arginine and aspartic acid
-Found in cyanobacteria, used as a nitrogen storage mechanism |
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Term
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Definition
-Makes DNA, RNA, phospholipids
-Stored as polyphosphate granules (also called volutin or metachromatic granules)
-Used in biosynthesis, could act as an E reserve |
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Term
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Definition
*Pretty
-Storage granule
-End product from bacteria that use hydrogen sulfide as an electron donor
-Can be used to generate E as food |
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Term
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Definition
1. Carboxysomes
2. Gas vacuoles
3. Magnetosomes |
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Term
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Definition
-CO2 fixing bacteria
-autotrophic bacteria
-contain the enzyme ribulose-1,5 biphosphate carboxylase (rubisco), enzyme used for CO2 fixation |
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Term
Gas vacuoles
where are they found?
what do they do? |
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Definition
-Found in aquatic, photosynthetic bacteria and archaea
-Vacuole is an aggregate of thousands of cylindrical single protein structures called gas vesicles
-Provide buoyancy, adaptation to optimum environmental conditions |
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Term
Magnetosomes
where are they found?
what do they do? |
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Definition
-Found in aquatic bacteria, formed of magnetite (Fe3O4)
-Particles arranged in chains (magnetosome chain)
-Cytoskeletal protein MamK is thought to be responsible for establishing a framework upon which the chain may form
-Magnetite particles for orientation in earth's magnetic field: Goes towards the food sediments (mostly comes from dead cells) |
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Term
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Definition
-Complex structure of protein and RNA
-Site of protein synthesis
-70s ribosome is composed of 2 units: 50s and 30s
--50s (LSU): 23S rRNA + 5S rRNA + ribosomal proteins
(some archaea have an additional 5.85 rRNA unit in the LSU, similar to eukaryotes
--30S (SSU): 16S rRNA + ribosomal protein
*Smaller than eukaryotic ribosomes
-Prokarytoic ribosomes> 70s
-Eukaryotic ribosomes> 80s
*S= Svedburg unit: 10^-13 seconds (rate of sedimentation measure) |
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Term
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Definition
| 16S rRNA + ribosomal protein |
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Term
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Definition
| 23S rRNA + 5S rRNA + ribosomal proteins |
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Term
The nucleoid
shape
location
bound |
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Definition
*irregularly shaped region
*location of chromosome - usually 1/cell
* not membrane-bound |
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Term
| The prokaryotic chromosome |
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Definition
-closed circular, double-stranded DNA molecule
-looped and coiled extensively
-nucleoid proteins probably aid in folding
-Located in the nucleoid |
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Term
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Definition
*Small, double stranded DNA molecules that can exist and replicate independently of the chromosome
*Most plasmids are circular, some are linear
*Have relatively few genes present (exceptions?)
*Genes on plasmids are not essential to host but may confer selective advantage, loss of plasmid is called CURING
-Some can integrate to the chromosome (episomes)
-Extrachromosomal |
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