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20 Cards in this Set
- Front
- Back
Describe the structure, composition, and functions of prokaryotic cell walls.
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Cell wall maintains cell shape, provides physical protection and prevents the cell from bursting in a hypotonic enviroment. wall made up of peptidoglycan, a network of modified-sugar polymers crosslinked by short polypeptides.
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Distinguish between the structure and staining properties of gram-positive and gram-negative bacteria.
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Gramp positive has thick cell wall and is purple
Gram negative has thin cell wall and is pink. outer membrane. |
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Explain why prokaryotes are unable to grow in very salty or sugary foods, such as cured meats or jam.
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It puts the prokayotes in a hypertonic enviroments which dehydrates the cell
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What are antibiotics?
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Chemical secreted by one microbe to kill another microbe.
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What are the limitations of antibiotics?
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Gram negatives outermembrane impedes entry of the drug.
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6.State the function(s) of each of the following prokaryotic features:
a.capsule b.fimbriae c.sex pilus d.nucleoid e.plasmid f.endospore |
Capsule- a sticky layer of polysaccharide or proteins. protects against dehydration.
Fimbriae- hair like proteins that help stick to their substrate or to one another. Sex pili- appendages that pull two daughter cells together prior to DNA transfer from one cell to another. Nucleoid- a region of cytoplasm that appears lighter than the surrounding cytoplasm in electron micrographs. Plasmids- smaller rings of separately replicating DNA. |
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Describe three processes that produce recombinant DNA in prokaryotes.
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Transformation- Uptake of "naked" DNA
Transduction- Aquisition of new DNA from phage Conjugation- Exchange of plasmids through a sex pilis. |
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Distinguish among photoautotrophs, chemoautotrophs, photoheterotrophs, and chemoheterotrophs.
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Photoautotrophs- Phoyosyenthetic organisms that capture light engery and use it to drive the synthesis of orangic compounds from CO2 or other inorganic carbon.
Chemoautotrophs- Need only a inorganic compund such as CO2 as a carbon source. Instead of using light as an energy source, they oxidize inorganic substances. Photoheterotrophs- Harness energy from light but must obtain carbon in organic from. Chemoheterotrophs- Must consume organic molecules to obtain both energy and carbon. |
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Distinguish among obligate aerobes, facultative anaerobes, and obligate anaerobes.
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Obligate aerobes-An organism that requires oxygen for cellular respiration and cannot live with out it.
Obligate anaerobes- an organism that only carries out fermentation or anaerobic respirationl such organisms cannot use oxygen and in fact may be poisoned by it. Facultative- An organism that makes ATIP by aerobic respiration if oxygen is present but thet switches to anaerobic resperation or fermatation if oxygen is not present. |
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Explain the importance of nitrogen fixation to life on Earth.
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Nitrogen is essential for the production of amino acids and nucleic acids in all organisms.
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Explain why some archaea are known as extremophiles. Describe the distinguishing features of extreme halophiles and extreme thermophiles.
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Archaea live in enviroments so extreme that few other organisms can survive there(extremeophiles).
Extreme halpophiles- live in highly saline enviroments Extreme thermophiles- Thrive in very hot enviornments. |
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Discuss the metabolism and environmental significance of methanogens.
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Methanogens- a group of archaea named for the unique way they obtain energy. They use CO2 to oxidize H2, releasing methane as a waste product. They live in extreme enviroments
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Distinguish among mutualism, commensalism, and parasitism. Provide an example of a prokaryote partner in each type of symbiosis.
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of its host.
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Distinguish between exotoxins and endotoxins and give an example of each.
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Exotoxin- proteins secreted by bacteria that cause illness.(Example is botox)
Endotoxins- Lipopolysaccharide attach to the outermembrane of a gram- bacteria.(Example typhoid fever) |
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Describe the evidence that suggests that the dangerous E. coli strain O157:H7 arose through horizontal gene transfer.
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Scientists sequenced the genome O157:H7 and compared it with the denome of harmless strain of E.coli called K-12. They discovered that 1000 out of 5000 genes in O157:H7 have no counterpart in K-12.
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Define bioremediation.
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bioremediation is the use of organisms to remove pollutants from soil, air, or water.
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Describe four ways humans use bacteria commercially.
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Humans can modify bacteria to produce vitamins, antibitotics, hormones, bioremediation.
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Define bacteriorhodopsin
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red membrane pigment
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Define opportunistic
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causing disease only under certain conditions, as when a person's immune system is impaired.
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Define saprobe
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any organism that lives on dead organic matter, as certain fungi and bacteria.
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