BI101J, UNSEEN LIFE ON EARTH, QUIZ 3 Carl Woese intended to ________ by examining the gene for ribosomes. * reconstruct a family tree for all organisms discover new pharmaceutical drugs find a cure for ribosomiasis all of the above none of the above Why are thermophiles important in the creation of a universal tree of life? They represent an unimportant side branch. They are amazingly similar to other eukarya. * They represent a life form that exists now in conditions very similar to those when life first emerged on Earth. all of the above none of the above Taq polymerase is an example of a(n) ________, and is important for its key role in ________ technology. simple molecule; cell-cell communication enzyme useful in photosynthesis; telecommunications * extremozyme; PCR all of the above none of the above Humans occupy which branch on the tree of life? * eukarya archaea prokarya all of the above none of the above Some organelles, such as the ________ , have their own ________. cell wall and membrane; DNA flagella and nucleosome; enzymes * mitochondria and chloroplast; DNA all of the above none of the above The characteristics listed in the question above suggest that these organelles were once _________ bacteria. photosynthetic or energy-producing independent free-living * all of the above none of the above Horizontal gene transfer is commonly found only among eukaryotic organisms. * one reason why apparently unrelated bacteria share some genes. rare in bacteria. all of the above none of the above Pathogenic bacteria rely on _______ to gain entry to the inside of a human cell. * cell-cell communication active transport one shouldn’t say, really all of the above none of the above Evaluate this statement: Millions of microbes may be found coexisting without harm with their human hosts. True; each of us has a large and complex community of fungi, bacteria, and protists living in and on us. True; although some populations of microbes may cause problems when they grow rapidly in response to the elimination of competitors by antibiotics. True; many of these microbes perform essential functions for us and we would not be healthy without them. * all of the above none of the above How is it that our mouths are home to bacteria that can live only in the absence of oxygen? Oxygen is consumed by our red blood cells. The mouth is normally a low oxygen environment. * Anaerobic bacteria live in crevices of our teeth and gums where little oxygen can penetrate. all of the above none of the above During bacterial conjugation, DNA is shuttled from one bacterium to another by means of a viral vector. genetic material is transferred from one dead, burst bacterium to another intact one. * genetic material is transferred though a conjugation tube from one living bacterium to another. all of the above none of the above In bacterial transformation, genetic material is transferred though a conjugation tube from one living bacterium to another. DNA is shuttled from one bacterium to another by means of a viral vector. * competent bacteria take small pieces of DNA across their cell walls and incorporate them into their own DNA. all of the above none of the above In bacterial transduction, * a virus conveys DNA from one bacterium to another. competent bacteria take small pieces of DNA across their cell walls and incorporate them into their own DNA. a transducer modulates the voltage of a bacterium. all of the above none of the above Transduction, conjugation, and transformation are three processes that are effective methods of preventing nosocomial illnesses. illuminate evolutionary relationships among the eukarya. * increase genetic diversity among bacteria by promoting the exchange of genetic material. all of the above none of the above Genetic engineering is the technology of ________, and is based on bacterial ________. * manipulating the genes of an organism; transduction, transformation, and conjugation increasing seed production; cell wall structure improving roadways; degradation of asphalt and concrete all of the above none of the above Which of the following is most likely to be responsible for the increases in nosocomial infections with antibiotic-resistant pathogens? increased numbers of patients in hospitals * horizontal gene transfer by conjugation and transformation coupled with strong natural selection the policies of health maintenance organizations all of the above none of the above You experience cold symptoms but your doctor won’t oblige your request for antibiotics. Why not? The doctor is concerned that viruses will develop resistance. * Colds are caused by viral infections; viruses are unaffected by antibiotics. Antibiotics are too expensive to be used for such low impact diseases. all of the above Earth’s first life forms were * heterotrophic anaerobic bacteria. heterotrophic aerobic bacteria. autotrophic bacteria. viruses. none of the above Active transport and diffusion are * the means bacteria use to take in substances from outside their cell walls. unimportant for living organisms. terms borrowed from the computer industry to describe the techniques used in genetic engineering. all of the above none of the above Heterotrophic organisms form their own energy-rich molecules from simple starting materials like CO2 and H2O. * absorb preformed energy-rich organic substances. are found in soil environments exclusively. all of the above none of the above