<p>BI 200 - Exam #2 Name Spring 2005 Lab Section</p><p>Disclaimer Consider each question, and answer each in the appropriate format (e.g., Multiple Choice). You may qualify your answer if you have reservations. If your comments have merit, you may receive partial or full credit.</p><p>Multiple Choice – 2 points each</p><p>1. Which of the following is not an energy requirement for a microorganism? a. biosynthesis b. active transport c. motility d. none of the above – all are requirements e. a, b, and c, - none of them are requirements</p><p>2. Anabolism is synonymous with a. catabolism b. metabolism c. biosynthesis d. parasitism</p><p>3. The net result of proton extrusion through the membrane is: a. acidification of the cytoplasm b. acidification of the medium outside the membrane c. a net formation of OH- inside the membrane d. energization of the membrane e. (b), (c), and (d)</p><p>4. Stromatolites dating back 2 billion years, when oxygen first appeared in the atmosphere, are rich in fossilized bacteria resembling modern a. Methanogens b. Cyanobacteria c. Green algae d. Amoeba 5. Which of the following statements best describes the occurrence of thermophilic organisms among the three lines of descent? a. Thermophilic organisms appear only in the bacteria b. Thermophilic organism are equally distributed among the archaea, bacteria, and eukarya c. Thermophilic organism occur among the archaea, bacteria, and eukarya, with archaea including the most extreme examples d. Microbes can’t grow at temperatures much higher than 98 oF</p><p>6. The upper temperature limit on growth of microorganisms discovered so far seems to be a. 98 oF b. 165 oC c. 212 oC d. 235 oC</p><p>7. Study of thermophilic bacteria from hot springs and other places around the world has led to a. the idea that life was possible in the early history of the Earth when temperatures were much higher. b. the discovery of a third form of life – archaea c. the complete sequencing of DNA from thermophiles and other organisms d. the use of heat-stable enzymes in biotechnology e. All of the above</p><p>8. Which of the following is a microbiologist from the University of Illinois who is credited with discovering the archaea? a. Dr. Thomas D. Brock b. Dr. William Schopf c. Dr. Carl R. Woese d. Dr. Norman Pace.</p><p>9. Which of the following is a microbiologist from the University of Wisconsin that pioneered the study of thermophilic bacteria in hot springs? a. Dr. Thomas D. Brock b. Dr. William Schopf c. Dr. Carl R. Woese d. Dr. Norman Pace.</p><p>10. Free parking. 2 free points 11. Which bacterium is an obligate aerobe? a. Escherichia b. Saccharomyces c. Paracoccus d. Zymomonas </p><p>12. Which is a bacterium that carries out ethanol fermentation? a. Streptococcus b. Saccharomyces c. Paracoccus d. Zymomonas </p><p>13. Which eukaryotes have mitochondria and carry out aerobic respiration? a. Algae b. Yeast c. Metazoa d. all of these e. none</p><p>14. Where in the mitchondrion does the electron transport chain occur? a. cristae b. thylakoid c. matrix d. stroma</p><p>15. Given the ΔG of formation, which of these would not be considered high energy? a. ATP, -31.8 kJ/mol b. PEP, -51.8 kJ/mol c. Glucose-6-phosphate, - 13.8 kJ/mol d. 1,3 bisphosphoglycerate, -52 kJ/mol</p><p>16. Geological evidence for the appearance of oxygen gas in the atmosphere is found in a. banded iron formations b. sulfur hot springs c. Jurassic park c. primordial soup</p><p>17. The air pockets in bread are due to which type of metabolism? a. aerobic respiration b. lactic acid fermentation c. ethanol fermentation d. photosynthesis</p><p>18-20. Triple free parking – 6 free points. Complete the following narrative about chemical evolution by circling the appropriate term in each parenthesis so that each sentence is accurate.</p><p>Astrophysical and geological evidence suggests the Earth is about (4000, 600 million, 4.5 x 109) years old. The early Earth was (much colder, much warmer, about the same temperature) as it is today. Gasses trapped in rocks from the period indicate that there was no (O2, H2O, CH4, N2) in the atmosphere then. In the first stage of chemical evolution the elements C, O, N, H, and S in the form of (polymers, monomers, gasses) combined to form many small organic compounds like (cheese, amino acids, DNA, trilobites). The energy to form the covalent bonds could have came from (ATP, dehydration reactions, lightning) cosmic rays, and volcanic activity. This process has been demonstrated in the laboratory in the (Harrad, Miller-Urey, Hershey-Chase) experiment. In the second round of chemical evolution even more complex (monomers, stromatolites, polymers) were formed from (monomers, stromatolites, polymers). </p><p>This could have happened through (dehydration, nuclear, symbiotic) reactions on exposed surfaces that underwent periodic wetting and drying. The most important of the complex molecules formed in the second stage was (O2, lipid, RNA). Like (DNA, lipid, protein) it has the potential to store information, and like (protein, polysaccharides, lipids) it has the potential to catalyze chemical reactions. (5) Yogurt is produced by fermenting milk sugar (lactose) to milk acid (lactic acid). The process is energetically favorable. Make an energy diagram indicating the reactants, the products, and the relative amounts of energy in the products and reactants. Indicate any other energy requirement for the reaction to proceed. Answer the questions related to the diagram.</p><p>Energy</p><p>Time</p><p>Questions</p><p>(1) Is G less than, greater than or equal to zero?</p><p>(1) What are the units used to measure the amount of energy?</p><p>(1 each) If enzymes are used to carryout the process, will they influence a.) the rate of the reaction, b.) the overall change in energy, and c.) the activation energy? Give a yes or no answer for each. a.) b.) c.)</p><p>(1) Why are there less calories in one cup of yogurt than one cup of milk? Hint: Calories are a measure of chemical bond energy. Where do the calories go?</p><p>(1) What is the genus name of bacterium is the “active” culture in Dannon yogurt? In the fermentation of glucose to ethanol and CO2, pyruvate and acetaldehyde are intermediates. Give the average oxidation numbers of the carbon atoms in each of the compounds. 1 point each</p><p>Glucose Pyruvate</p><p>C6H12O6 C3H4O3</p><p>Acetaldehyde Ethanol Carbon dioxide</p><p>CH3CHOH CH3CHOH CO2</p><p>Use one of the following terms that describes best the metabolism of the microorganism in each case. You may use a term more than once, or not at all. 1 point each</p><p>Chemoorganoheterotroph Chemolithoautotroph Photoautotroph Photoheterotroph a. A cyanobacterium growing by oxygenic photosynthesis, using CO2 as its sole source of carbon. </p><p> b. Hydrogenobacter growing on hydrogen gas as its fuel and CO2 as its sole source of carbon.</p><p> c. A yeast fermenting glucose.</p><p> d. Thiobacillus oxidizing H2S and reducing O2, using CO2 as its sole source of carbon. </p><p> e. Geobacter eating benzene and breathing iron. True/False. Indicate the validity of these statements by writing the whole word TRUE or the whole word FALSE before each of these statements. 1 point each.</p><p>______Coenzyme A is involved with electron transfer, while NAD+ is involved in transfer of carbon atoms. </p><p>______Proton extrusion through the membrane results in the storage of energy because of electrical and diffusion potential energy.</p><p>______Metabolism involves two basic kinds of chemical transformations, building up (biosynthetic) processes, called anabolism, and breaking down processes, called catabolism, which usually result in energy release.</p><p>______ATP is formed as a result of the proton motive force in aerobic respiration, but not anaerobic respiration</p><p>______Motility represents the greatest energetic cost to most microorganisms</p><p>______Humans are considered heterotrophs because they consume fats, proteins, and sugars for fuels.</p><p>______In anaerobic respiration electrons flow to molecules other than oxygen, like - 2- NO3 and SO4</p><p>______The presence of a membrane and the enzyme ATPase is indicative of substrate level phosphorylation</p><p>______Pyruvate acting as the electron acceptor to regenerate NAD+ from NADH is indicative of respiration </p><p>5 points. Describe in words and/or pictures the formation of stromatolites. Include the following terms: fossilized; biofilm; microbial mat. Indicate the relative thickness of each formation. Fill in the empty boxes for these familiar pathways. (1 point each).</p><p>Trait or Glycolysis Ethanol Fermentation Lactic Acid Fermentation Characteristic (stages I and II) (stage III reduction (Stage III reduction only) only) + Substrates Pyruvate, NAD , Pyruvate, NADH Pyruvate, NADH FAD+</p><p>Products Pyruvate, NADH, ATP</p><p>O2: consumed, Neither consumed or produced, both or produced neither?</p><p>Net ATP production per glucose</p><p>Mode of ATP formation (SLP, ETP, both, or none?) High Energy GTP None None Phosphorylated Intermediates</p><p>What is the key None None enzyme in this reaction sequence?</p>