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16 Cards in this Set
- Front
- Back
<p>Prokaryotes: Research & Technology</p>
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1. Used in modern research-proteins studied
2. Bioremediation-used to remove pollutants from water, soil, air 3. Metabolic factories for commercial products -Convert milk to yogurt & cheese -Produce acetone, butanol, vitamins & antibiotics |
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How do prokaryotes cause disease?
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1. Some directly invade tissue
2. Most produce poisons -exotoxins-proteins secreted by prokaryote -endotoxins-lipopolysacchrides (part of outer membrane of gram neg. bacteria) released when bacteria die |
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Movement
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1. Flagella (most common)
2. Corkscrew 3. Slime Threads *Taxis-directional movement in hetergeneous (non-uniform) environment -Chemotaxis (Chemical) -Phototaxis (Light) -Positive-Toward -Negative-Away |
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Archaea
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Important taxa (Clades)
1. Euryarchaeota-includes methanogens, halophiles, thermophiles 2. Crenarchaeota-includes thermophiles |
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Differences
Bacteria, Archaea, Eukaryotes |
Bacteria Archaea Eukaryotes Nuclear Envelope?
NO NO YES Organelles w/ Membranes? NO NO YES Circular Chromosome? YES YES NO |
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Which is more dangerous, Gram Negative or Gram Positive?
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GRAM NEGATIVE!
1. Lipoplysacchrides in cell wall toxic-induce fever 2. Outer membrane protects against host's defenses 3. More resistant to antibiotics *Penicillin inhibits x-link formation, ruins cell wall function |
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Peptidoglycan
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Only present in Prokaryotes!
Responsible for Gram Stain! Definition- sugars x-linked w/ polypeptides (proteins) |
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Symbiosis
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Def.- ecological relationship between organisms of diff. species in direct contact. Host=bigger Symbiont=smaller
1. Mututalism-both benefit 2. Commensalism- 1 benefits, the other is neither harmed not helped 3. Parasitism- 1 benefits at the other's expense |
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Nutrition
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1. Phototroph-uses light energy
2. Chemotroph-uses chemicals for energy 3. Autotroph-need only CO2 (inorganic) 3. Heterotroph-require at least one organic nutrient |
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Nutrition Combinations
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1. Photoautotroph-photosynthetic organisms use light energy to drive synthesis of organic compounds from CO2
2. Chemoautotrophs-need only CO2, but oxidize inorganic substances for energy 3. Photoheterotroph-use light for energy, obtain carbon in organic form 3. Chemoheterotrophs-consume organic molecules for energy ex. carbon |
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How can prokaryotes withstand harsh conditions?
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Endospore-second copy of DNA that is dehydrated (metabolic processes cease) and forms a hard shell.
Revives when conditions are favorable. |
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Prokaryotic vs. Eukaryotic
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1. Lack compartmentaliation by membranes
2. Infolded regions of plasma membrane (performs functions organelles perform in euk.) 3. Smaller, simpler genomes -plasmids, circular singular chromosome 4. Ribosomes smaller & differ in protein content *erythromycein & tetracyline bind to these & block protein synthesis |
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Reproduction
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Binary Fission-copy chromosome, split into 2 daughter cells
Growth-refers to increase in population, not individual size |
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Genetic Variation
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1. Mutation
2. Horizontal Gene Transfer -Transformation-cell takes genes from environment -Conjugation-direct transfer from cell to cell -Transduction-viruses transfer genes from cell to cell |
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Functions of Cell Wall
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1. Maintains Shape
2. Physical Protection 3. Prevents burtsing in a hypotonic environment *Hypotonic-water is forced into cell, can make it burst *Hypertonic-salt concentration outside higher, dehydrates cell |
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Prokaryote Structure
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1. Most unicellular-some aggregate and form colonies
2. Shape -Spheres (Cocci) -Rods (Bacillus) -Helices (Spirilla, Spirochetes) 3. Tiny-diameter 1-5 microns |