Exam 24: Early Life and the Diversification of Prokaryotes

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

Use the information in the following paragraph to answer the next few questions. 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. 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. -What should be true of the cell wall of this bacterium?

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.

Which of the following is least associated with the others?

Use the information in the following paragraph to answer the next few questions. 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. 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's ability to survive in a human who is taking penicillin pills may be due to the presence of which of the following? 1. penicillin-resistance genes 2) a secretory system that removes penicillin from the cell 3) a gram-positive cell wall 4) a gram-negative cell wall 5) an endospore

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

If new genetic variation in the experimental populations arose solely by spontaneous mutations, then the most effective process for subsequently increasing the prevalence of the beneficial mutations in the population over the course of generations is

Bacteria perform the following ecological roles. Which role typically does not involve symbiosis?

Which of the following is the correct sequence of events in the origin of life? I. formation of protobionts II) synthesis of organic monomers III) synthesis of organic polymers IV) formation of DNA-based genetic systems