Biology, Eighth Edition (Raven)

Chapter 28: Prokaryotes

Post Test

Ratios of carbon isotopes determined for many substances. If a scientist were to try to determine a biological origin for organic chemicals in a rock sample, he would look for (p. 540)
A)organic molecules, as they can only form through enzyme-mediated reactions.
B)the presence of carbon-fixing organelles such as chloroplasts, as they are required for any significant uptake of 12C.
C)stromatolites, which are always found in regions capable of large amounts of carbon fixation.
D)lower ratios of 12C to heavier isotopes in the inorganic material surrounding the sample than the sample itself.
E)higher ratios of 12C to heavier isotopes in the inorganic material surrounding the sample than the sample itself.
The three-domain (Woese) system of phylogeny incorporates standard molecular approaches to classification but emphasizes (p. 544)
A)cell membrane biochemistry.
B)rRNA sequence comparisons between organisms.
C)the method of obtaining and processing nutrients.
D)a and b are mostly emphasized in the three-domain system
E)None of the above is emphasized because molecular discrimination of different types of organisms is unambiguous.
A method that some bacterial cells can undertake to survive adverse conditions is (p. 548)
A)to form a thick layer of hairs or pili, which insulate it from the environment.
B)development of flagella to flee the dangerous area.
C)establishment of endospores, which survive the stress and germinate when conditions improve.
D)development of internal membranes which allow for a larger variety of biochemical reactions.
E)hibernation until conditions improve.
If an F+ cell is put into a culture consisting only of F- cells, (p. 549)
A)eventually the cell types will change until an equal amount of F+ and F- cells exist in the culture.
B)the fertility plasmid will be passed from cell to cell much like a relay race, until all cells have hosted it at one time or another.
C)almost all cells will become F+, with a few of them becoming the Hfr type.
D)the plasmid will integrate and excise into the chromosome of most of the recipient cells until genes are randomly distributed throughout the culture.
E)F+ cells will have a selective advantage over the F- cells, eventually forming a new species.
An example of exaptation (use of a structure for a new purpose than that in which it originally evolved) is the transfer of toxins using a membrane protein complex and the _________ from which it originally evolved. (p. 554)
A)surface pili
B)flagellum collar
C)peptidoglycan coat
It is important to complete a course of antibiotics when they've been prescribed by a physician because (p. 555)
A)the body destroys most of the antibiotics until a certain threshold has been consumed to allow treatment.
B)if the antibiotics are prematurely stopped, some pathogens may remain alive due to their partial resistance to the antibiotic. Natural selection may reinforce this resistance.
C)antibiotics are expensive, so not taking them all is a drain on health resources.
D)the body may develop antibodies against the antibiotic and so increasing blood levels is essential to maintain its activity.
E)taking the antibiotics over a long period of time will wear down the infection until it is too tired to continue being infectious.
The nitrogen in the atmosphere is made available to ecosystems through the action of soil microbes by (p. 557)
A)breaking the triple bond in N2 gas and creating ammonia.
B)decomposing dead organisms.
C)deamination of polypeptide subunits.
D)All of the above
E)None of the above
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