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20 Cards in this Set

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Describe the structure, composition, and functions of prokaryotic cell walls.
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.
Distinguish between the structure and staining properties of gram-positive and gram-negative bacteria.
Gramp positive has thick cell wall and is purple
Gram negative has thin cell wall and is pink. outer membrane.
Explain why prokaryotes are unable to grow in very salty or sugary foods, such as cured meats or jam.
It puts the prokayotes in a hypertonic enviroments which dehydrates the cell
What are antibiotics?
Chemical secreted by one microbe to kill another microbe.
What are the limitations of antibiotics?
Gram negatives outermembrane impedes entry of the drug.
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.
Describe three processes that produce recombinant DNA in prokaryotes.
Transformation- Uptake of "naked" DNA
Transduction- Aquisition of new DNA from phage
Conjugation- Exchange of plasmids through a sex pilis.
Distinguish among photoautotrophs, chemoautotrophs, photoheterotrophs, and chemoheterotrophs.
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.
Distinguish among obligate aerobes, facultative anaerobes, and obligate anaerobes.
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.
Explain the importance of nitrogen fixation to life on Earth.
Nitrogen is essential for the production of amino acids and nucleic acids in all organisms.
Explain why some archaea are known as extremophiles. Describe the distinguishing features of extreme halophiles and extreme thermophiles.
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.
Discuss the metabolism and environmental significance of methanogens.
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
Distinguish among mutualism, commensalism, and parasitism. Provide an example of a prokaryote partner in each type of symbiosis.
of its host.
Distinguish between exotoxins and endotoxins and give an example of each.
Exotoxin- proteins secreted by bacteria that cause illness.(Example is botox)
Endotoxins- Lipopolysaccharide attach to the outermembrane of a gram- bacteria.(Example typhoid fever)
Describe the evidence that suggests that the dangerous E. coli strain O157:H7 arose through horizontal gene transfer.
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.
Define bioremediation.
bioremediation is the use of organisms to remove pollutants from soil, air, or water.
Describe four ways humans use bacteria commercially.
Humans can modify bacteria to produce vitamins, antibitotics, hormones, bioremediation.
Define bacteriorhodopsin
red membrane pigment
Define opportunistic
causing disease only under certain conditions, as when a person's immune system is impaired.
Define saprobe
any organism that lives on dead organic matter, as certain fungi and bacteria.