Exam 24: Early Life and the Diversification of Prokaryotes

Which of the following is least associated with the others?

The first genes on Earth were probably

Assuming that each possesses a cell wall, which of these prokaryotes should be expected to be most strongly resistant to plasmolysis in hypertonic environments?

If archaeans are more closely related to eukaryotes than to bacteria, then which of the following is a reasonable prediction?

Please use the following information to answer the question(s) below. In Figure 24.1, data are presented from an eight-year experiment in which 12 populations of Escherichia coli, each begun from a single cell, were grown in low-glucose conditions for 20,000 generations. Each culture was introduced to fresh growth medium every 24 hours. Occasionally, samples were removed from the populations, and their fitness in low-glucose conditions was tested against that of members sampled from the ancestral (common ancestor) E. coli population. Figure 24.1 -E. coli cells typically make most of their ATP by metabolizing glucose. Under the conditions of this experiment, what should be true of E. coli's generation time (especially early in the course of the experiment, but less so later on)?

Scientists hypothesize that prokaryotes evolved before eukaryotes because

Which statement about the domain Archaea is true?

Which of the following is an accurate characteristic of bacterial cell walls?

Why can prokaryotic populations be magnitudes larger than populations of multicellular eukaryotes? I. Prokaryotes are small. II. Prokaryotes reproduce by binary fission. III. Prokaryotes often have short generation times. IV. Prokaryotes have cells walls primarily made of cellulose.

Suppose bacteria are grown on a petri dish that contains nutrient agar and the antibiotic ampicillin. After observing the bacteria growth on the plate for two days, you notice that only some of the bacteria have survived. What is a plausible explanation for your observations?

Please use the following information to answer the question(s) below. A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from bacteriophages and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan. -This bacterium derives nutrition by digesting human intestinal contents (in other words, food). Humans lacking this bacterium have no measurable reproductive advantage or disadvantage relative to humans who harbor this bacterium. Consequently, the bacterium can be properly described as which of the following? 1) symbiont 2) endotoxin 3) mutualist 4) commensal

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?

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 structure(s)? 1) nucleoid region 2) endospore 3) fimbriae 4) plasmids

Please use the following information to answer the question(s) below. A hypothetical bacterium swims among human intestinal contents until it finds a suitable location on the intestinal lining. It adheres to the intestinal lining using a feature that also protects it from bacteriophages and dehydration. Fecal matter from a human in whose intestine this bacterium lives can spread the bacterium, even after being mixed with water and boiled. The bacterium is not susceptible to the penicillin family of antibiotics. It contains no plasmids and relatively little peptidoglycan. -This bacterium derives nutrition by digesting human intestinal contents (in other words, food). Thus, this bacterium should be an

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, then the result should be

Which of these statements about prokaryotes is correct?

If all prokaryotes on Earth suddenly vanished, which of the following would be the most likely and most direct result?

Please use the following information to answer the question(s) below. In Figure 24.1, data are presented from an eight-year experiment in which 12 populations of Escherichia coli, each begun from a single cell, were grown in low-glucose conditions for 20,000 generations. Each culture was introduced to fresh growth medium every 24 hours. Occasionally, samples were removed from the populations, and their fitness in low-glucose conditions was tested against that of members sampled from the ancestral (common ancestor) E. coli population. Figure 24.1 -If new genetic variation in the experimental populations arose solely by spontaneous mutations, then the most effective process for subsequently increasing the number of individuals that possess all of these beneficial mutations is

Which of the following is an important source of endotoxin in gram-negative species?

The table depicts characteristics of five prokaryotic species (A-E). Use the information in the table to answer the following question(s). Table 24.1 -Which species should be able to respond most readily to taxes (plural of taxis)?