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| 1 | |
Archaebacteria and bacteria differ in |
| | A) | gene architecture. |
| | B) | cell wall structure. |
| | C) | gene translation machinery. |
| | D) | plasma membrane structure. |
| | E) | all of these. |
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| 2 | |
We can expect that one out of every ____ bacteria will have a mutant characteristic. |
| | A) | 100 |
| | B) | 200 |
| | C) | 500 |
| | D) | 1000 |
| | E) | 5000 |
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| 3 | |
Genetic recombination occurs in bacteria through the transfer of |
| | A) | pili. |
| | B) | plasmids. |
| | C) | endospores. |
| | D) | autospores. |
| | E) | gametes. |
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| 4 | |
Chemolithoautotroph bacteria include |
| | A) | halophiles. |
| | B) | myxobacteria. |
| | C) | spirochetes. |
| | D) | Nitrifiers. |
| | E) | cyanobacteria. |
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| 5 | |
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 |
| | 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. |
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| 6 | |
The three-domain (Woese) system of phylogeny incorporates standard molecular approaches to classification but emphasizes |
| | 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. |
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| 7 | |
A method that some bacterial cells can undertake to survive adverse conditions is |
| | 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. |
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| 8 | |
If an F+ cell is put into a culture consisting only of F- cells, |
| | 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. |
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| 9 | |
It is important to complete a course of antibiotics when they've been prescribed by a physician because |
| | 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. |
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| 10 | |
The nitrogen in the atmosphere is made available to ecosystems through the action of soil microbes by |
| | A) | breaking the triple bond in N2 gas and creating ammonia. |
| | B) | decomposing dead organisms. |
| | C) | deamination of polypeptide subunits. |
| | D) | hydrolysis of starch. |
| | E) | None of the above. |
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| 11 | |
Microfossils about 3.5 billion years old have been found. They represent |
| | A) | the first plants. |
| | B) | fossilized remains of biologically-derived organic molecules. |
| | C) | remains of prokaryotic cells, the first organisms. |
| | D) | deposits of specific isotopes of carbon that are most easily explained by biological metabolism. |
| | E) | remnants of Archaea ancestors. |
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| 12 | |
The chromosomes of bacteria are typically |
| | A) | linear, made of single-stranded DNA, and found in their nucleus. |
| | B) | circular, made of singe-stranded DNA, and found in their nucleus. |
| | C) | linear, made of double-stranded DNA, and found in their nucleoid region. |
| | D) | circular, made of double-stranded DNA, and found in their nucleoid region. |
| | E) | linear, made of double-stranded RNA, and found in their nucleoid. |
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| 13 | |
Gram-negative bacteria are so-named because they quickly die in the presence of the Gram reagent. |
| | A) | True |
| | B) | False |
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| 14 | |
Horizontal gene transfer is the movement of genes from one species to another. In prokaryotes, this can most often occur via |
| | A) | transformation. |
| | B) | transduction. |
| | C) | conjugation. |
| | D) | All of these cause horizontal gene transfer. |
| | E) | None of these allow horizontal gene transfer. |
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| 15 | |
The term "autotroph" refers specifically to |
| | A) | cells which can obtain their own food by engulfing other organisms. |
| | B) | organisms which get their energy by harnessing the energy from spontaneous chemical reactions. |
| | C) | cells which use energy from light reactions but obtain carbon from organic molecules. |
| | D) | metabolic strategies during which carbon is harnessed from inorganic CO2 sources. |
| | E) | metabolism involving organic carbon and energy sources. |
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