Exam 27: Bacteria and Archaea

The following table depicts characteristics of five prokaryotic species (A-E). Use the information in the table to answer the question. Which two species might be expected to cooperate metabolically, perhaps forming a biofilm wherein one species surrounds cells of the other species?

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?

Which of the following traits do archaeans and bacteria share?

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. - Which term best describes what has occurred among the experimental populations of cells over this eight-year period?

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?

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 metabolising glucose. Under the conditions of this experiment, E. coli generation times in the experimental lines and low-glucose conditions should ________.

The pathogenic prokaryotes that cause cholera are ________.

The predatory bacterium Bdellovibrio bacteriophorus drills into a prey bacterium and, once inside, digests it. In an attack upon a gram-negative bacterium that has a slimy cell covering, what is the correct sequence of structures penetrated by B. bacteriophorus on its way to the prey's cytoplasm?

Sexual reproduction in eukaryotes increases genetic variation. In prokaryotes, transformation, transduction, and conjugation are mechanisms that increase genetic variation. A fundamental difference between the generation of genetic variation in the two domains is ________.

Nitrogenase, the enzyme that catalyses nitrogen fixation, is inhibited whenever free oxygen (O₂) reaches a critical concentration. Consequently, nitrogen fixation cannot occur in cells wherein photosynthesis produces free O₂. Consider the colonial aquatic cyanobacterium, Anabaena, whose heterocysts are described as having "...a thickened cell wall that restricts entry of O₂ produced by neighbouring cells. Intercellular connections allow heterocysts to transport fixed nitrogen to neighbouring cells in exchange for carbohydrates". Given that the enzymes that catalyse nitrogen fixation are inhibited by oxygen, what mechanism might nitrogen-fixing prokaryotes use to protect these enzymes from oxygen?

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

Healthy individuals of Paramecium bursaria contain photosynthetic algal endosymbionts of the genus Chlorella. When within their hosts, the algae are referred to as zoochlorellae. In aquaria with light coming from only one side, P. bursaria gather at the well-lit side, whereas other species of Paramecium gather at the opposite side. The zoochlorellae provide their hosts with glucose and oxygen, and P. bursaria provides its zoochlorellae with protection and motility. P. bursaria can lose its zoochlorellae in two ways: (1) if kept in darkness, the algae will die; and (2) if prey items (mostly bacteria) are absent from its habitat, P. bursaria will digest its zoochlorellae. -A P. bursaria cell that has lost its zoochlorellae is aposymbiotic. If aposymbiotic cells have population growth rates the same as those of healthy, zoochlorella-containing P. bursaria in well-lit environments with plenty of prey items, then such an observation would be consistent with which type of relationship?

The thermoacidophile Sulfolobus acidocaldarius lacks peptidoglycan, but still possesses a cell wall. Which of the following statements is likely to be an accurate description of this species?

Photoautotrophs use

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 phagocytes, bacteriophages, and dehydration. Faecal 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. -Adherence to the intestinal lining by this bacterium is due to its possession of ________.

Use the following information and figure to answer the question. The sea slug Pteraeolidia ianthina (P. ianthina) can harbour living dinoflagellates (photosynthetic protists) in its skin. These endosymbiotic dinoflagellates reproduce quickly enough to maintain their populations. Low populations of the dinoflagellates do not affect the sea slugs very much, but high populations (> 5 x 105 cells/mg of sea slug protein) can promote sea slug survival. Percent of sea slug respiratory carbon demand provided by indwelling dinoflagellates. - If we assume that carbon is the sole nutrient needed by sea slugs to drive their cellular respiration, then based on the graph, during which season(s) is it least necessary for P. ianthina to act as a chemoheterotroph?

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). - What process is occurring at Time C that is decreasing the DNA content?

In prokaryotes, new mutations accumulate quickly in populations, while in eukaryotes, new mutations accumulate much more slowly. The primary reasons for this are ________.

Plantlike photosynthesis that releases O₂ occurs in

Which of the following is least associated with the others?