Chapter 16: The Origin of Life and the Precambrian Evolution

1.	Evidence that RNA is ancient, as predicted by the RNA World hypothesis for the origin of life, include(s) which of the following? [Hint]
2.	Spiegelman et al. demonstrated that QB RNA changed over the course of many serial transfers from one test tube system to another. Given all their findings, which of the following best explains the changes they observed? [Hint]
3.	In what important way did Beaudry and Joyce extend the work done on RNA evolution by Spiegelman and colleagues? [Hint]
4.	In one or two brief sentences, give your own interpretation of what Gerald Joyce meant when he wrote that "Once an RNA enzyme with RNA replicase activity is in hand, the dreaming stops and the fun begins."   To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
5.	The interpretation that the amino acids found in the Murchison meteorite were, in fact, extra-terrestrial in origin came from what line(s) of evidence? [Hint]
6.	Although chemists have had some success in identifying plausible mechanisms for the prebiotic synthesis of amino acids, sugars, and nitrogenous bases, the "warm little pond" that molecular biologists dream about is still a "prebiotic chemist's nightmare." Why? [Hint]
7.	The second step in the Oparin-Haldane model is the formation of biological polymers from building blocks in the prebiotic soup. Although polymer synthesis can happen in water, so does _____. Ferris et al. have proposed a solution to this problem by demonstrating that _____ can act as a catalyst, speeding up the rate of polymer formation. [Hint]
8.	We are unlikely to find evidence of life much earlier than 3.7-3.85 billion years ago because [Hint]
9.	To be useful in estimating deep phylogeny, a gene sequence must have several important characteristics. Pick two of these and briefly describe why they're important and how the small subunit rRNA gene meets the relevant criteria [Hint] To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
10.	Which of the following accurately characterize(s) the universal phylogeny Woese and colleagues developed? [Hint]
11.	The figure illustrates a universal phylogeny based on the HMGCoA reductase gene. Archaeoglobus fulgidus is unambiguously an archaean, but it is placed in the Bacteria based on its HMGCoA sequence. The most parsimonious explanation for this pattern is that A. fulgidus acquired a bacterial HMGCoA gene by . [Hint]
12.	Based on the dates of the oldest known fossils of eukaryotes and cyanobacteria, the first branching in the universal phylogeny most likely took place no more recently than [Hint]
13.	Briefly explain the rRNA evidence supporting Margulis' endosymbiotic hypothesis for the origin of chloroplasts and mitochondria, being clear to frame your answer in terms of predictions and tests. Use the figure to answer the question. [Hint] To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.
14.	The tufA gene, which codes for a translation factor active only in chloroplasts, is found only in the cpDNA of some green algae, in the cp and nuclear DNA of other green algae, and only in the nuclear genome of the flowering plant Arabidopsis. The most likely explanation for this pattern is [Hint]
Answer choices in this exercise are randomized and will appear in a different order each time the page is loaded.