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Unformatted text preview: The following questions were used for a version of the Mic102 final exam; though I wont be using this format this year, they are good questions that you should be able to answer. Were all human: large, multicellular eukaryotes with numerous complicated organ systems that we use to do amazing stuffsuch as appreciate what it means to be human. Our mere existence is due to a long chain of extremely unlikely events; an understanding of biology allows us to better appreciate how special our existence is. 1. Chlorophyll is an accidental invention. It was invented only once, in an ancestor of modern bacteria, over 3.5 billion years ago; its structure bears obvious similarity to a component of electron transport chains. In three sentences, describe (1) how chlorophyll is structurally and functionally similar to a specific component of many electron transport chains, (2) how chlorophyll is used by some bacteria for ATP production (NOT autotrophy; be sure to name this process), and (3) compare this process with respiration. (12 points) 2. Chlorophyll was invented once in the history of bacteria. However, in the modern world, we see two basic ways of using chlorophyll. In the Heliobacteria and Chlorobi , we see chlorophyll in photosystem I. In the Chloroflexi and Proteobacteria , we see chlorophyll in photosystem II. In one sentence, how do photosystem I and photosystem II differ? (4 points) 3. PS I (in Chlorobi ) and PS II (in Chloroflexi ) are used for exactly the same thing: making ATP. In two sentences, explain how these different types of chlorophyll could evolve from the same ancestor; state whether this is an example of genetic drift or selection, and why. (8 points) 4. In a sample of bacteria taken from the environment, you may find members of both the Chlorobi and the Chloroflexi . Of course, you could tell who is who by sequencing their rRNA, but that is a pain. In two sentences, describe what you would need to distinguish between the two in an environmental sample using FISH. In an additional sentence, describe how and why you could tell who was who simply by using just fluorescence microscopy or a spectrophotometer. (8 points) 5. In one sentence, explain how having just one photosystem increased the ability of some bacteria to grow autotrophically. Be sure to bear in mind what is required for autotrophy, and how a photosystem helps produce this. (4 points) 6. Only one lineage of Bacteriathe Cyanobacteriahas both photosystem I and photosystem II. In a composed paragraph of five sentences, propose a process by which this happened; be sure to explain what events were necessary, and why they were unlikely. (20 points) 7. The evolution of a single cell with two distinct photosystems is highly unlikelyso there must be some selective advantage to having two photosystems that allowed such cells to survive. In one sentence, what is the advantage of having two photosystems? (4 points) 8. One model cyanobacterium is the marine bacterium Prochlorococcus. Prochlorococcus....
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This note was uploaded on 04/05/2011 for the course MIC 102 taught by Professor Appleman during the Fall '08 term at UC Davis.
- Fall '08