Exam 27: Bacteria and Archaea

Leaf-cutter ants harvest plant leaves and bring them back to their nests. There, in the warm, moist environments of their underground nests, they grow fungi (Leucoagaricus) that they then eat. These ants also host bacteria on their exoskeleton. Another fungus, Escovopsis, kills Leucoagaricus when the ants are removed from the nest. Knowing that the bacteria on the ants are in the same phylogenetic group of other bacteria that produce antibiotics, which of the following research hypotheses is most likely correct?

Genetic variation in bacterial populations cannot result from

The following question refers to the figure. In this eight-year experiment, 12 populations of E. 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. Compare the bacteria in the figure above in generation 1 and generation 20,000. The bacteria in generation 1 have a greater ________.

Use the following information and graph to answer the question. The figure below depicts changes to the amount of DNA present in a recipient cell that is engaged in conjugation with an Hfr cell. Hfr cell DNA begins entering the recipient cell at Time A. Assume that reciprocal crossing over occurs (in other words, a fragment of the recipient's chromosome is exchanged for a homologous fragment from the Hfr cell's DNA). How is the recipient cell different at Time D than it was at Time A?

The following table depicts characteristics of five prokaryotic species (A-E). Use the information in the table to answer the following question. Which two species should have much more phospholipid, in the form of bilayers, in their cytoplasms than most other bacteria?

The following question refers to the figure. In this eight-year experiment, 12 populations of E. 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. E. coli cells typically make most of their ATP by metabolizing glucose. Under the conditions of this experiment, E. coli generation times in the experimental lines and low-glucose conditions should ________.

When a virus infects a bacterial cell, often new viruses are assembled and released when the host bacterial cell is lysed. If these new viruses go on to infect new bacterial cells, the new host cells may not be lysed. What is the most plausible explanation for this?

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 ________.

Recently, a microbe that is able to digest cellulose was discovered in a hot spring with an average temperature of 95°C. Predict the group to which this microbe most likely belongs.

Which of the following describe all existing bacteria?

Which of the following involves metabolic cooperation among prokaryotic cells?

Jams, jellies, preserves, honey, and other foods 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 ________.

Which of the following observations about flagella is accurate and is consistent with the scientific conclusion that the flagella from eukaryotes and bacteria evolved independently?

The following question refers to the figure. In this eight-year experiment, 12 populations of E. 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. The cells in the 12 cell lines grown in low-glucose conditions showed the effects of which of the following processes?

Use the following information and graph to answer the question. The figure below depicts changes to the amount of DNA present in a recipient cell that is engaged in conjugation with an Hfr cell. Hfr cell DNA begins entering the recipient cell at Time A. Assume that reciprocal crossing over occurs (in other words, a fragment of the recipient's chromosome is exchanged for a homologous fragment from the Hfr cell's DNA). Which two processes are responsible for the shape of the curve at Time B?