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100 Biology Exam 1 (version 0) February 28, 2006 Choose the BEST answer to each question. 1. What statement(s) best reflect(s) the process component of the Cell Theory? A. The cell is the smallest unit of life. B. All cells have mitochondria. C. All living organisms are made of cells. D. All cells come from pre-existing cells.. E. C. and D 2. In the experiment designed by Pasteur to test the spontaneous generation hypothesis he used two types of flasks: one with a straight neck and one with a swan neck. The cell theory hypothesis predicts that: A. Cells will appear in neither flask. B. Cells will appear in the straight-necked flask, but will not appear in the swan-necked flask. C. Cells will appear in the swan-necked flask, but will not appear in the straight-necked flask. D. Cells will appear in both the straight-necked and swan-necked flasks. E. None of the above. 3. Linnaeus system of classifying living organisms as belonging to either the Plant Kingdom or the Animal Kingdom was replaced by Whittakers Five Kingdom system because _______________________________ A. Linnaeus system did not account for the fundamental division between prokaryotes and eukaryotes. B. fungi, such as mushrooms, were not green and therefore belonged in the animal kingdom rather than the plant kingdom where Linnaeus placed them. C. some animals can make their own food and are therefore like plants. D. Linnaeus taxonomic classifications did not include domains for bacteria, archaea and eukarya. E. A. and D. 4. Current taxonomic classification attempts to reflect the phylogeny of existing species i.e., their historical relationships. This change in the goal of taxonomy resulted mainly from _________________________________ A. the need to account for the difference between prokaryotes and eukaryotes. B. the fact that all living organisms are related to each other by virtue of having a common ancestor. C. advances in microscopy that allowed biologists to study the contents of individual cells in detail. D. Woeses findings about the difference between base sequences in the small subunit of ribosomal RNA in different organisms. E. the mounting evidence for evolution as a model that explained the enormous diversity of living organisms. 5. Which of the following statements about giraffes represent predictions derived from the food Biol 100 Exam 1 Spring 2006, version 0, p. 1 competition hypothesis and is(are) also supported by evidence? 1. Male giraffes with longer necks feed with their necks extended more often than female giraffes. 2. Giraffes with longer necks feed with their necks fully extended more often than giraffes with shorter necks. 3. Giraffes typically feed with their necks fully extended in order to reach foliage near the tops of trees. A. B. C. D. E. 1 2 3 1 and 3 none of the statements 6. What is entropy and why is it important in the context of living systems? A. Entropy is a measure of disorder and living systems are generally disordered. B. Living systems survive by using energy to reduce entropy (or to maintain entropy constant) within their boundaries. C. The total entropy in the universe increases over time. D. Living systems cause the entropy within their boundaries to increase over time. E. C. and D. 7. In the absence of specific carrier proteins, which of the following can diffuse relatively easily across the plasma membrane of a cell? A. sodium and potassium ions B. amino acids C. small proteins D. glycerol E. ATP molecules 8. Researchers who used liposomes to examine the effect of cholesterol content on phospholipid membrane permeability found that A. as the temperature increased, cholesterol generally increased membrane permeability. B. as the temperature decreased, cholesterol generally decreased membrane permeability. C. the higher the temperature, the less the effect cholesterol had on membrane permeability and fluidity. D. the higher the amount of cholesterol in the membrane, the more fluid and permeable the membrane was. E. at all temperatures, the greater the amount of cholesterol in the membrane, the less permeable the membrane was. 2 9. The cells of fish that live in the near-freezing waters off Alaska need to maintain membrane fluidity and permeability despite the low temperature. Therefore they are likely to have cell membranes that contain ___________ cholesterol and ___________ phospholipids with short, kinked fatty acid tails than the cell membranes of fish living in tropical waters. A. less; fewer B. more; more C. less; more D. more; fewer E. both B. and D. make correct statements. 10. Pure lipid bilayer membranes are effectively impermeable to ions and glucose. How, then, are such substances able to diffuse through the plasma membrane of cells? A. By means of transport proteins. B. By means of channel proteins or ionophores. C. By means of active transport proteins. D. By osmosis. E. A and B. 11. The red blood cell membrane is impermeable to both sucrose and hemoglobin. If a red blood cell is placed into a hypotonic sucrose solution (i.e., the concentration of sucrose outside the cell is less than the concentration of hemoglobin inside), A. water will enter the cell by osmosis and the cell will swell. B. water will leave the cell by osmosis and the cell will shrink. C. water will enter the cell by osmosis, and the cell will shrink. D. water will leave the cell by osmosis, and the cell will swell. E. no water will move into or out of the cell, and the cell will not swell or shrink. 12. How does osmosis differ from simple diffusion? A. Osmosis involves water movement, diffusion involves solute movement B. Osmosis involves a semipermeable membrane, diffusion occurs even when there is no membrane involved. C. Osmosis can be described as the diffusion of water from a region of high solute concentration to a region of low solute concentration. D. A and B are correct statements E. B and C are correct statements 13. The concentration of potassium is much higher on the inside of cells than it is on the outside. How is this potassium ion concentration established and maintained? A. By potassium ion channel proteins in the cell membrane. B. By ionophores like valinomycin that facilitated the diffusion of K+ into the cell. C. By active transport of K+ from the outside to the inside of the cell. Biol 100 Exam 1 Spring 2006, version 0, p. 3 D. By active transport of Na+ from the inside to the outside of the cell. E. By a combination of facilitated diffusion and active transport. 14. Individuals with cystic fibrosis have an abnormal CFTR protein. Their sweat is unusually salty because ___________________ A. sodium and chloride ions diffuse from skin cells into their sweat ducts. B. sodium and chloride ions are actively transported from skin cells into their sweat ducts. C. the skin cells lining their sweat contain ducts little or no ATP. D. sodium ion channels in skin cells are blocked by CFTR. E. sodium and chloride ions in their sweat cannot diffuse into the skin cells that line their sweat ducts 15. If ATP on one side of the interior of a cell were to be used up, the ATP on the other side of the cell would take a long time to diffuse to that location. This is a statement of the diffusion problem which is A. a problem for all cells. B. a serious problem in large prokaryotes like archaea and unicellular plants. C. not a problem in either eukaryotes or prokaryotes, since eukaryotic cells have organelles. D. not a problem since there are no reactions inside cells that can use up ATP on only one side of a cell. E. not a problem since diffusion is not that slow. In fact, diffusion is fairly rapid. 16. All living cells have one or more internal, membrane-bound organelles. This statement is A. false, because viruses do not have membrane-bound organelles. B. true, since membrane-bound organelles are found in all plant and animal cells. C. true, since the nucleus is a membrane-bound organelle. D. false, because most prokaryotes (bacteria and archaea) do not have membrane-bound organelles. 17. Mitochondria and chloroplasts_______________________ A. are found in all plant cells. B. have a single plasma membrane. C. contain their own DNA. D. both use oxygen as the final electron acceptor. E. none of the above 18. When cells run out of fuel to generate ATP, what happens? A. They can no longer replicate or repair their DNA. B. They can no longer actively transport (pump) ions and amino acids across cell membranes. C. They cannot synthesize new proteins or phospholipids. D. They cannot contract, or move materials contained within vesicles. E. All of the above. 4 19. What was(were) the critical experiment(s) that indicated the nucleoplasmin tail was the site of the nuclear localization signal? A. Nucleoplasmin tails with a radioactive label attached were injected into the cytoplasm and were later found in the nucleus. B. Radiolabeled nucleoplasmin cores injected into the cytoplasm were later found in the nucleus. C. Large, cytoplasmic proteins that had been fused with a specific, nucleoplasmin amino acid tail sequence were injected into the cytoplasm and were later found in the nucleus. D. Nucleoplasmin tails with a radioactive label attached were found in the nucleus, whereas unlabeled tails remained in the cytoplasm. E. A. and C. 20. What is the purpose of the "chase" in a pulse-chase experiment? A. The chase allows the researcher to observe the spatial or temporal distribution of a labeled molecule over time. B. The chase molecules carry an alternate label to provide the researchers with a second way to track the pathway under study. C. The chase allows researchers to slow the reaction so that the pulsed molecules can be more easily tracked over time. D. The chase is required to neutralize the radioactively labeled molecules that were introduced during the "pulse" phase of the experiment. E. The chase is not actually essential and can be skipped in certain cases. 21. What observation gave rise to the signal hypothesis? A. The tail and head subunits of ribosomes were separately labeled and injected into the lumen of the rough ER. B. Proteins synthesized in the rough ER were found to be 20 amino acids longer than the same proteins synthesized by isolated ribosomes in vitro (no ER present). C. Proteins synthesized in the rough ER were found to be 20 amino acids shorter than the same proteins synthesized by isolated ribosomes in vitro (no ER present). D. A signal sequence was discovered by accident because it bound to a signal recognition particle (SRP). E. Proteins synthesized in the rough ER were found to be 20 amino acids shorter than the same proteins synthesized in the smooth ER. 22. The zipcode tag attached to certain proteins that targets them for transport to lysosomes is _______________ A. exportin. B. fructose1,6diphosphate. C. an amino acid signal sequence. D. mannose6phosphate. E. a lysosomal receptor enzyme. Biol 100 Exam 1 Spring 2006, version 0, p. 5 23. The mixing of purified microtubules with transport vesicles and ATP does not result in movement of the vesicles. Why? A. Kinesin is missing. B. Intermediate filaments are missing. C. Glucose is missing. D. Actin is missing. E. Oxygen is missing. 24. In aerobic respiration, what is the ultimate fate of the 6, reduced carbon atoms in a glucose molecule? A. Each of the carbon atoms combines with atmospheric oxygen to produce CO2. B. Half of the carbon atoms are used to make fats and phospholipids, while the other half are used to make ATP. C. The six carbon atoms of glucose produce two pyruvate molecules which then enter the Krebs cycle after being converted to acetyl-CoA. D. The carbon atoms of glucose are oxidized by NAD+ to produce CO2. E. Each carbon atom combines with ADP to produce 2 molecules of ATP. 25. In eukaryotes, the enzymes of the Krebs cycle are located in the ____________ . A. cristae of mitochondria B. matrix of mitochondria C. cytoplasm D. intermembrane compartment of mitochondria E. nucleus 26. When glucose is oxidized in cells to provide energy, the oxygen in the atmosphere combines with the carbon in the glucose to make CO2. A. True B. False 27. High energy electrons are donated to the electron transport system of mitochondria by A. water B. NADH C. FADH D. NAD+ E. B. and C. 28. Which of the following products of glycolysis contains the least potential energy per molecule? A. NADH 6 B. ADP C. ATP D. pyruvate 29. NAD+ and FAD are A. reduced enzymes B. oxidized enzymes C. reduced electron carriers D. oxidized electron carriers E. electron transport system proteins 30. Which molecule has the most chemical energy stored in its bonds? A. ATP B. pyuvate C. glucose D. fatty acid 31. The statement that oxygen is the final electron acceptor refers to the fact that A. oxygen accepts electrons from the electron transport chain at the end of cell respiration. B. oxygen accepts electrons from glucose to form carbon dioxide. C. oxygen accepts electrons from NADH to make NAD+. D. oxygen accepts electrons from hydrogen atoms to form water. E. oxygen is at a very high energy state and can accept electrons from anything with a lower energy state. 32. In plant cells that lack chloroplasts, ATP is produced by A. anaerobic respiration B. aerobic respiration. C. type II photosynthesis D. none of the above, since plant cells without chloroplasts cannot produce ATP 33. At night, plant cells _______________________ A. consume O2 and carbohydrates, and release CO2. B. consume O2 and produce carbohydrates C. consume CO2 and release O2. D. consume CO2 and light energy, and produce carbohydrates Biol 100 Exam 1 Spring 2006, version 0, p. 7 ... View Full Document

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