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BIOL 1407 CH.27
| Question | Answer |
|---|---|
| Mycoplasmas are bacteria that lack cell walls. On the basis of this structure concerning mycoplasmas should be true? | They are subject to lysis in hypotonic conditions. |
| Though plants, fungi, and prokaryotes all have cell walls, we place them these observations comes closest to explaining the basis for placing these well before relevant data from molecular systematics became available? | Their cell walls are composed of very different biochemicals. |
| Which statement about bacterial cell walls is false? | Cell walls prevent cells from dying in hypertonic conditions. |
| The predatory bacterium, Bdellovibrio bacteriophorus, drills into a prey and digests it. In an attack upon a gram-negative bacterium that has a slimy cell sequence of structures penetrated by B. bacteriophorus on its way to the... | 4,1,3,2. Capsule, membrane composed mostly of lipopolysaccharide, peptidoglycan, membrane composed of mostly phospholipids. |
| Jams, jellies, preserves, honey, and other foodstuffs with high sugar content hardly ever become contaminated by bacteria, even when the food containers are left open at room temperature. This is because bacteria that encounter such an environment | Undergo death by plasmolysis. |
| In a bacterium that possesses antibiotic resistance and the potential to persist through very adverse conditions, such as freezing, drying, or high temperatures, DNA should be located within, or be part of, which structures? | 1, 2, 4. Nucleoid region, endospore, plasmids. |
| Which two structures play direct roles in permitting bacteria to adhere to each other, or to other surfaces? 1. capsules 2. endospores 3. fimbriae 4. plasmids 5. flagella | 1, 3. Capsules, fimbriae. |
| Prokaryotic ribosomes differ from those present in eukaryotic cytosol. Because of this, which of the following is correct? | Some antibiotics can block protein synthesis in bacteria without effects in the eukaryotic host. |
| Which statement about the genomes of prokaryotes is correct? | Prokaryotic genomes are composed of circular DNA. |
| If a bacterium regenerates from an endospore that did not possess any of the plasmids that were contained in its original parent cell, the regenerated bacterium will probably also | Lack antibiotic-resistant genes. |
| Although not present in all bacteria, this cell covering often enables cells that possess it to resist the defenses of host organisms, especially their phagocytic cells. | Capsule |
| Prokaryotes' essential genetic information is located in the | Nucleoid |
| Which of the following is an important source of endotoxin in gram-negative species? | Cell wall |
| Chloramphenicol is an antibiotic that targets prokaryotic (70S) ribosomes, but not eukaryotic (80S) ribosomes. Which of these questions stems from this observation, plus an understanding of eukaryotic origins? | If chloramphenicol inhibits prokaryotic ribosomes, should it not also inhibit mitochondrial ribosomes? |
| In a hypothetical situation, the genes for sex pilus construction and for tetracycline resistance are located together on the same plasmid within a particular bacterium. If this bacterium readily performs conjugation involving a copy of this plasmid? | The rapid spread of tetracycline resistance to other bacteria in that habitat. |
| Regarding prokaryotic genetics, which statement is correct? | Mutation is a primary source of variation in prokaryote populations. |
| Which of these statements about prokaryotes is correct? | They divide by binary fission, without mitosis or meiosis. |
| Which of the following obtain energy by oxidizing inorganic substances energy that is used, in part, to fix CO2? | Chemoautotrophs |
| Mitochondria are thought to be the descendants of certain alpha proteobacteria. No longer able to lead independent lives because most genes originally present on their chromosome have moved to the nuclear genome. Which phenomenon accounts for the movement | Horizontal gene transfer |
| Carl Woese and collaborators identified two major branches of prokaryotic evolution. What was the basis for dividing prokaryotes into two domains? | Genetic characteristics such as ribosomal RNA sequences |
| Which statement about the domain Archaea is true? | Genetic prospecting has recently revealed the existence of many previously unknown archaean species. |
| If archaeans are more closely related to eukaryotes than to bacteria, then which of the following is a reasonable prediction? | Archaean ribosomes should be larger than typical prokaryotic ribosomes. |
| Which of the following traits do archaeans and bacteria share? 1. composition of the cell wall 2. presence of plasma membrane 3. lack of a nuclear envelope 4. identical rRNA sequences | 2 and 3. Presence of plasma membrane. Lack of nuclear envelope. |
| Assuming that each of these possesses a cell wall, which prokaryotes should be expected to be most strongly resistant to plasmolysis in hypertonic environments? | Extreme halophiles |
| The thermoacidophile, Sulfolobus acidocaldarius, lacks peptidoglycan, but still possesses a cell wall. What is likely to be true of this species? | 2, 4, and 5. It is an archaean. The optimal pH of its enzymes will lie below pH 7. It could inhabit certain hydrothermal springs. |
| A fish that has been salt-cured subsequently develops a reddish color. You suspect that the fish has been contaminated by the extreme halophile, Halobacterium. Which of these features of cells removed from the surface of the fish, if confirmed, would supp | 2, 3, 4, and 5. Cell walls that lack peptidoglycan. Cells that are isotonic to conditions on the surface of the fish. Cells containing bacteriorhodopsin. The presence of very large numbers of ion pumps in its plasma membrane. |
| The termite gut protist, Mixotricha paradoxa, has at least two kinds of bacteria attached to its outer surface. One kind is a spirochete that propels its host through the termite gut. A second type of bacteria synthesizes ATP, some of which is used by the | 1, 3, and 4. Mutualism. Symbiosis. Metabolic cooperation. |
| In general, what is the primary ecological role of prokaryotes? | Breaking down organic matter |
| If all prokaryotes on Earth suddenly vanished, which of the following would be the most likely and most direct result? | The recycling of nutrients would be greatly reduced, at least initially. |
| In a hypothetical situation, a bacterium lives on the surface of a leaf, where it obtains nutrition from the leaf's nonliving, waxy covering while inhibiting the growth of other microbes that are plant pathogens. If this bacterium gains access to the insi | 2, 4, 1. Mutualist. Parasite. Nutrient recycler. |
| Foods can be preserved in many ways by slowing or preventing bacterial growth. Which of these methods should be least effective at inhibiting bacterial growth? | Closing previously opened containers: prevents more bacteria from entering, and excludes O2. |
| Broad-spectrum antibiotics inhibit the growth of most intestinal bacteria. Consequently, assuming that nothing is done to counter the reduction of intestinal bacteria, a hospital patient who is receiving broad-spectrum antibiotics is most likely to become | Deficient in certain vitamins and nutrients. |
| This bacterium's ability to survive in a human who is taking penicillin pills may be due to the presence of | 2, 3, or 5. A secretory system that removes penicillin from the cell. A gram-positive cell wall. An endospore. |
| What should be true of the cell wall of this bacterium? | It has an outer membrane of lipopolysaccharide. |
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gummybears21