Final Exam Spring 2001

Final Exam Spring - Biology 255 – Drs Glaser& Mallery May 7 2001 – 2:00pm-4:30pm SA 126 FORM 0 FINAL EXAM Spring Semester 2001 Directions

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Unformatted text preview: Biology 255 – Drs. Glaser & Mallery May 7, 2001 – 2:00pm-4:30pm SA 126 FORM 0 FINAL EXAM Spring Semester 2001 Directions: CHOOSE THE BEST ANSWER FROM AMONG THOSE GIVEN. Part 1. Dr. Glaser – material since last test. 1. Mitochondria are closely related to ? a) Retroviruses b) Transposones c) Procaryotes 2. The docking of vesicles at targets requires ? a) v-Snares b) t-Snares c) v-Snares and t-Snares that are complementary and bind to each other 3. Proteins that are destined to the cytoplasmic membrane are oriented in the Golgi so that the portion of the protein that will face the outside of the cell faces (think carefully) ? a) The lumen of the Golgi b) The cytoplasm around the Golgi 4. You expect the pH in trans Golgi to be relative to ER ? a) pHGolgi < pH ER b) pHGolgi > pH ER 5. After endocytosis, cytoplasmic membrane proteins are ? a) All returned to cell surface b) Some are returned to cell surface 6. Steroid hormones, for example cortisone, control gene transcription by ? a) Intercalating in DNA and distorting the helix b) Binding to a specific steroid binding protein that acts as an RNA polymerase c) Binding to a specific steroid binding protein that binds to an enhancer sequence for steroid sensitive genes 7. The preferred arrangement of a lipid bilayer (lowest energy) in contact with water is ? a) Sheet b) Helix c) A closed sphere 8. The cytoplasmic membrane of eucaryotic cells contains glycoproteins and glycolipids. You expect the carbohydrate portion of these molecules to be primarily ? a) Facing the inside of the cell b) Facing the outside of the cell c) Both 9. It is believed that mitochondria originated from ? a) Aerobic bacteria b) Anaerobic bacteria 10. Complex carbohydrates are covalently linked to many proteins on asparagine residues. Which of the following statements is correct? a) The carbohydrates are built by adding one sugar residue at a time to the protein in the ER b) The carbohydrates are pre-assembled on a lipid (dolichol) and then transferred to protein in the ER 11. When glucagon is added to hepatocytes (liver cells) the level of cAMP in these cells is elevated and glucose is released by the cells. Caffeine is an inhibitor of cAMP phosphodiesterase. Do you expect (think very carefully) a) Caffeine to potentiate the action of glucagon, i.e., small amounts of glucagon become more effective b) Caffeine to inhibit the action of glucagon c) Cannot answer based on these facts 12. Cholera toxin is an enzyme that modifies some G proteins so that their GTPase activity is abolished. When you add cholera toxin to hepatocytes in tissue cultures in the presence of epinephrine (adrenaline) cAMP levels rise in these cells, and remain high even after adrenaline is removed. In this absence of cholera toxin, removal of adrenaline results in an immediate drop in cAMP. If you could examine in these cells treated with cholera toxin the state of the α, β, γ subunits of G protein, would you expect ? a) To find most of the G proteins as α, β, γ complex b) Most of the G protein as α subunit separate from β, γ complex 13. In a classical experiment in embryology, the implantation of supernumerary limbs in chick embryos resulted in ? a) Neuronal death b) Survival of more neurons than in a normal embryo c) No effect on the number of neurons Bil 255 S 01 – Final Exam – Form 0 – pg 2 14. You’re given an antibody that allows you to identify the thyroxine receptor & localize it in the cell. You expect to find ? a) The receptor in the absence of thyroxine is in the nucleus b) The receptor in the presence of thyroxine is in the cytoplasm c) The receptor in the presence of thyroxine is in the nucleus 15. ACTH addition to adrenal cortisol cells results in increased production of cAMP and increased synthesis of cortisol. Epinephrine addition to skeletal muscle results in increased production of cAMP but not in increased synthesis of cortisol, yet the action of both hormones is mediated by cAMP. Furthermore, ACTH has no effect on muscle cells. These observations reflect the fact that ? a) Muscle cells lack the transcription regulators that control synthesis of the enzymes that make cortisol b) Muscle cells do not have a receptor for ACTH c) Both a and b apply 16. Upon addition of epidermal growth factor (EGF) to cells, the EGF receptor is phosphorylated at multiple sites on tyrosine residues. This phosphorylation ? a) Is irrelevant to signal transduction by EGF b) Provides sites for activation of other proteins in the cell c) Each site is specific for a different pathway d) b and c apply 17. The best description of a cell cycle is ? a) A series of random events that culminate in cell division b) A series of sequential events that culminate in cell division c) A process with multiple check points d) a and b apply 18. MPF (M/phase promoting factor) is best described as a ? a) Cyclin b) Protein kinase d) A complex of a specific cyclin and a specific protein kinase e) b and c apply c) A complex of cyclin and protein kinase 19. Normal cells stop transit through the cell cycle when DNA is damaged. This process ? a) Requires DNA ligase and p53 b) Requires p53 and expression of p21 d) a and b apply and results in inactivation of S phase cyclin-CdK e) b and c apply and results in inactivation of S phase cyclin-CdK c) Occurs in S phase 20. Oncogenes act as dominant agents to control cell growth. You expect a mutation in retinoblastoma genes to behave as ? a) Dominant mutation b) Recessive mutation 21. Which of the following events are likely to predispose a cell to become a cancer cell ? a) Loss of p53 gene b) Loss of DNA repair protein c) Decrease in cellular ATP levels d) a and c apply e) a and b apply 22. Which of the following statements is/are correct ? a) Cells have a single check point before they enter the cell cycle. b) Cells have multiple check points that control progression through the cell cycle c) Cell size determines in part whether cells can enter the cell cycle d) a and c apply e) b and c apply The next six (6) questions are related. 23. You discover a new hormone, which stimulates the growth of α-cells of the pancreas, which makes glucagon. After much effort, you clone the gene for the hormone and obtain it in large quantities. It codes for a small protein molecule weight of 10,000. You inject the hormone into rats and after several weeks the animals look ill. You measure their blood glucose and find it to be (pick the most likely answer)? a) High b) Low 24. You work very hard to find a receptor for this hormone on α -cells of the pancreas and you identify a protein present on the surface of the α-cells to which the hormone binds. As part of your work you have prepared a series of monoclonal antibodies against this presumed-hormone receptor and find that one of them mimics the action of the hormone, but a monovalent fragment of this antibody has no effect. From your vast knowledge about hormone receptors, you presume that this receptor belongs to a ? a) Family of hormone receptors that increase the level of cAMP in cells b) Family of hormone receptors that function as tyrosine specific protein kinases Bil 255 S 01 – Final Exam – Form 0 – pg 3 25. Since your new hormone stimulates cell growth, you examine the level of phosphorylation of the retinoblastoma protein (which is important for the growth of α-cells) eight to ten hours after the addition of hormone to cells & find a) The retinoblastoma protein is not phosphorylated b) The retinoblastoma protein is phosphorylated 26. You want to better understand how this hormone works and you develop conditions for growing α-cells in a Petri dish in the laboratory. You are however quite careless and you grow your cells in an incubator next door to your dentist, who does a lot of dental X-rays. To your horror you discover that most of your cells have died. You rush over to see your dentist and discover that she forgot to shield her X-ray machine. After two days of crying you return to your laboratory and discover that some of your α-cells have survived, look peculiar, and are growing in the Petri dish. You decide to measure the presence of p53 in these cells and are likely to find a) Normal levels of p53 b) Low or non-functional levels of p53 ++ 27. You return to the study of the hormone receptor in normal cells and decide to measure Ca levels in the cytoplasm of these cells before and after the addition of hormone. You find that the addition of hormone increases the level of ++ -7 -5 Ca from 10 M to 10 M. You decide to measure the activity of phospholipase C in these cells and expect to find that after the hormone addition ? a) Phospholipase C levels are elevated b) Phospholipase C levels are reduced c) Phospholipase C levels are unchanged 28. One of the earliest effects of the addition of the hormone to cells is a change in intracellular pH, the cells transiently ++ become more alkaline. You pre-treat cells with ouabain to block Na /K ATPase and find that this alkalinization of cells is abolished. This observation is ? ++ a) Consistent with alkalinization being the result of activation of Na /H antiport ++ b) These results argue against a role of Na /H antiport in the alkalinization of these cells 29. Children born with I cell disease lack the ability to phosphorylate mannose residues in glycoproteins destined to go to lysosomes. Think carefully. Would you expect the lysosomal enzymes to ? a) Remain in the ER b) Be secreted by cells c) Degrade the trans Golgi 30. Which of the following statements is correct ? a) Only the á subunit of the G protein has biological activity when released from the á ß ã complex b) The á subunit as well as the Bã complex have biological activity 31. The interaction of hormones with cells elicit biological responses on a variety of time scales. (pick the best answer) a) changes in the activity of pre-existing enzymes occurs in hours b) changes in the activity of pre-existing enzymes occurs in seconds to minutes c) Enzyme levels change in minutes d) a and c apply e) b and c apply ++ 32. Ca levels in the cytoplasm often occur following the binding of specific hormones to the cell. The source of the Ca can be ? a) The extracellullar fluid b) The endoplasmic reticulum c) Both d) Neither ++ 33. Which of the following changes in a normal cell would increase the likelihood that the cell would become malignant ? (Read carefully, assume all proteins listed are functional in this cell.) a) Loss of p53, activation of Ras, activation of caspases b) Loss of retinoblastoma protein, activation of ERB-13 (a growth factor receptor, loss of DNA repair protein c) High levels of camp, loss of insulin receptor, high levels of Ca++, loss of E.cadherin (a cell adhesion molecule) 34. You examine the cells in a melanoma (skin tumor) in a female. Recall that in females only one X-chromosome is functional in a given cell. Do you expect ? a) All cells in the tumor to have the same transcriptionally active X chromosome b) Each X chromosome is transcriptionally active in 50% of the cells. 35. In order for a polypeptide hormone to affect a cell's metabolism, the cell must have ? a) A nuclear receptor for the protein b) A cytoplasmic receptor for the protein c) A receptor on the cytoplasmic membrane Bil 255 S 01 – Final Exam – Form 0 – pg 4 Part 2. Dr. Mallery – material since last test. 36. The higher the partition coefficient of a solute, the greater its ? a. solubility is water b. its permeability across a membrane d. hydrophilicity e. none of these is correct c. ability to bind proteins 37. A channel protein transports ? a. lipids across a membrane b. proteins across a membrane c. ATP across a membrane d. ions and small hydrophilics across a membrane e. none of these is correct 38. Uniport transport may also be ? a. antiport b. electrogenic c. coupled antiport d. none of these is correct 39. An ion channel that opens/closes in response to cell potential is a ? a. voltage gated channel b. ligand gated channel c. stress activated channel d. patch clamp channel e. none of these is a correct choice 40. The technique used to measure the current changes in an individual ion channel as it opens or closes is ? a. Nernst potential b. stress activation c. patch clamping d. resting potential e. none of these is correct 41. Which of the following is a causative factor of the cell’s resting potential ? a. unequal distribution of ions as Na, K, and Cl across the cell membrane b. active and electrogenic transport of Na and K by the Na pump c. a greater permeability of K out of a cell than Na into a cell d. presence of protein anions inside a cell e. choose this answer if all of the above are correct 42. A self propagating change in the cell’s membrane resting potential that requires a living cell and has a stimulus threshold may be referred to as ? a. resting potential b. ion channel potential c. hyperpolarization d. action potential e. none of these is a correct choice 43. The depolarization of cell’s membrane during an action potential is due to ? a. ligand gated channel b. K gated channel c. stress activated channel d. Na gated channel e. none of these is correct 44. An excitatory post synaptic potential is due to a ? a. ligand gated channel b. Cl gated channel d. K gated channel e. none of these is correct c. stress activated channel 45. In a pulse-chase experiment which one of the following is most likely being measured ? a. the size of an ion channel b. the direction of an ion channel c. the length of time of S period d. the number of microtubules present e. none of these is correct 46. Gamma (γ) or ring tubulin is found inside a ? a. centriole b. microtubule organizing center e. none of these is a correct choice c. contractile ring d. phragmoplast 47. The spindle microtubules which connect the opposite ends of a cell during chromosomal division are the ? a. chromosomal MT’s b. kinetochore MT’s c. polar MT’s d. astral MT’s e. none of these is a correct choice 48. A number of anticancer drugs function by interfering with MT assembly or disassembly. Which of the following is such a drug? a. leptotene b. cholchicine c. spindilin d. phragmoplin e. none of these 49. Which of the following is more likely to be responsible for cytokenesis in animal cells ? a. anaphase A b. phragmoplast c. contractile ring e. none of these is a correct choice d. taxol Bil 255 S 01 – Final Exam – Form 0 – pg 5 50. The binding of homologous chromosomes together during sexual cell division is accomplished via ? a. diakenesis b. synaptonemal complexes c. random assortment d. mitosis e. none of these is a correct choice Part 3. Dr. Glaser – cumulative material 51. The original evidence that DNA is the genetic material of cells is based on ? a) Chemical analysis of DNA b) Analysis of chromosomes c) Transformation of bacteria by DNA d) a and b apply 52. When DNA is chemically damaged, DNA repair requires: (think carefully) ? a) Excision of both strands of damaged DNA b) Excision of damaged nucleotides c) Filing in gaps with DNA polymerase and sealing with DNA ligase d) a and c apply e) b and c apply 53. Synthesis of RNA requires ? a) Four ribonucleoside triphosphate and RNA polymerase b) Promoter and an initiation of transcription site c) Regulatory proteins that control transcription d) a and b apply e) a, b and c apply 54. The function of tRNA’s is to translate mRNA is ? a) There is only one tRNA for each amino acid c) here are multiple tRNA’s for all amino acids b) There are multiple tRNA’s for some amino acids 55. Ribosomes are best described as ? a) A large set of proteins and DNA b) Two particles the large and small ribosomal subunit each containing RNA and protein c) Particles containing an RNA which can function as an enzyme (catalyst) d) a and c apply e) b and c apply 56. Proteins are synthesized by ribosomes ? a) Starting at their amino end b) Starting at their carboxyl end 57. When a ribosome reaches the end of a mRNA it releases the completed protein ? a) Attached to tRNA b) As a free polypeptide 58. Phosphorylation of proteins (enzymes) by ATP catalyzed by specific protein kinases is used to ? a) Modify the charge of protein b) Change the enzymatic activity of the protein (an on/off switch) 59. Regulators of transcription in procaryotes and eucaryotes are ? a) Always positive regulators, i.e., activate transcription b) Are always negative regulators c) Both types are functional in cells 60. Enhancer sequences are ? a) DNA sequences that control DNA replication b) DNA sequences distant from gene that binds regulatory proteins that control gene expression 61. When phosphatidyl ethanolamine is present in a lipid bilayer you expect the ethanolamine to be ? a) At the center of the bilayer b) In the aqueous phase 62. Higher organisms often contain multiple proteins which have apparently evolved from a common ancestral gene. The most likely origin of these is (for example, hemoglobin) ? a) Unequal crossing over b) Bacterial infections c) Insertion of enhancer molecules close to the initiation site of gene transcription 63. You have cloned and sequenced all of human chromosome 10. You expect ? a) All the coding sequences are on one strand (the same strand of DNA) b) Both strands of DNA contain coding sequences c) The exons on both strands of DNA base pair with each other Bil 255 S 01 – Final Exam – Form 0 – pg 6 64. The dideoxy nucleotide method for sequencing DNA is based on ? a) The chain termination of DNA polymerase action after a dideoxy nucleotide is incorporated into DNA b) The separation of DNA molecules that differ in length by one nucleotide c) The knowledge of the beginning sequence of the DNA to synthesize a primer d) a and b apply e) a, b and c apply 65. When two cells are fused, after a short period of time you expect ? a) All membrane proteins are now randomly distributed b) Some membrane proteins are constrained from free diffusion 66. Some proteins form pores that allow entry or exit of hydrophilic (water soluble) molecules from cellular compartments. You expect such proteins to traverse membranes ? a) Once b) Twice c) Multiple times 67. Gatorade is a bad tasting mixture of glucose and NaCl, very effective in restoring glucose to the body. You attempt to improve the taste of Gatorade by replacing NaCl with either NH4Cl or KCl, and neither works. you consult a student well trained in BIO 255 who explains to you that ? a) b) c) + NaCl is required to match the Na concentration in blood NaCl facilitates the exit of glucose into blood stream from intestinal epithelial cells NaCl is required for glucose transport into intestinal epithelial cells 68. Active transport is the movement of molecules across a membrane against its concentration gradient. Cells have evolved several mechanisms to accomplish this. Which of the alternatives below describe these mechanisms? a) A GTP driven glucose transport system and a light driven pump b) Light driven pumps, ATP driven pumps and coupled transporters c) ATP driven transport of sugars, and ion driven transport of amino acids d) All are correct + + 69. In a cell under physiological conditions activation of the Na /H antiport will ? a) Increase cellular pH (i.e., cell becomes alkaline) b) Decrease cellular pH (i.e., cell becomes more acid) c) The question cannot be answered 70. The synthesis of most membrane proteins in cells is best described as ? a) Initiated in the endoplasmic reticulum (ER) b) Requires a signal sequence c) Some mitochondrial proteins are synthesized in the cytoplasm and others in the mitochondria d) All of these statements are correct 71. In a classical experiment Avery McLeod and McCarthy showed that extracts of smooth strains Streptococcus Pneumonia could transform rough strains to smooth strains. The difference between the two is the ability of smooth strains to synthesize a capsular polysaccharide. They further showed ? a) That the transforming principle was the capsular polysaccharide b) Was DNA c) Required specific proteins as well as DNA 72. Helicase is required for DNA replication. It ? a) Unwinds the DNA helix b) Unwinds the DNA helix in an ATP dependent manner c) Neither statement is correct 73. The origin during evolution of various cellular membranes and organelles in eucaryotes has been subject of much debate. Based on current thinking you would expect ? a) Mitochondrial ribosomes to resemble procaryotic ribosomes b) Cytoplasmic ribosomes in eucaryotic cells to resemble procaryotic ribosomes. Bil 255 S 01 – Final Exam – Form 0 – pg 7 Questions 74 and 75 are related: 74. Two children are born in a hospital at the University of Florida. Since Gators are not careful, the blood samples taken from the two mothers may have been mislabeled and there is a possibility that the parents took home the wrong child. Before alarming anybody, a bright UM graduate suggests a RFLP analysis to see whether she can solve the problem. The results with a probe are ? Parents A Mother Father Child X Parents A took home ______ Parents B Mother Father ________ ______ ______ ________ ________ ______ ______ ______ Child Y Parents B took home ________ ______ a) Child X does not belong to Parents A b) Child Y does not belong to Parents B c) One child could belong to either parent d) a and b are correct e) a and c are correct 75. The experiment in question 74 was repeated using a different probe for a different region of the genome. (Think carefully) a) The new probe can confirm or negate the positive identification of the parents of either child b) If the probe used in question 24 leads to the conclusion that a child can not belong to a particular set of parents, can the new probe reverse the conclusion c) a and b apply d) The question can not be answered Part 4. Dr. Mallery – cumulative material From the plot of the two enzymes shown to the right answer questions 76 – 79. 77. The Km of Enz B is closest to ? a. 10 umoles per min b. 0.3 umoles glucose c. 8 umoles glucose d. 2 umoles glucose e. none of these is correct 12 umoles per min 76. What is the maximum velocity of Enz A ? a. 2 umoles glucose b. 6 umoles per min c. 10 umoles per min d. 24 umoles glu e. none of these is correct 10 8 6 4 2 0 0.001 78. Which enzyme, A or B, has the greater affinity for its substrate a. Enz A b. Enz B c. neither enzyme, they both have the same affinity d. none of these is a correct answer 79. A competitive inhibitor of Enz B would ? a. lower the Vmax but have the same Km c. physical bind to and remove some of the enzyme B e. none of these is correct 0.25 0.3 0.4 1 2 4 8 12 umoles glucose Enz A Enz B b. have the same Vmax, but lower the Km d. keep the same Km and Vmax 24 Bil 255 S 01 – Final Exam – Form 0 – pg 8 80. The class of enzymes known as dehydrogenases are often involved in hydrogen transfers are called the ? a. transferases b. hydrolyases c. isomerases d. ligases e. none of these 81. The person responsible for some of the earliest, definitive X-ray diffraction pictures of DNA was ? a. Rosy Franklin b. Linus Pauling c. James Watson d. Fred Sanger e. none of these 82. An embryonic cell that continually divides is a(n) ? a. sperm cell b. stem cell c. epithelial cell d. prion e. none of these 83. Cells are able to capture and/or gather energy by which of the following mechanisms. a. capture of light energy by pigments b. redox reactions c. hydrogen ion pumps d. electron transfer e. choose this answer if all of these is correct 84. Which of the following is an extremophile organism ? a. egg cell b. stem cell c. halophile cell d. fibroblast cell e. none of these is correct 85. While life on Earth can exhibit an amazing diversity of appearance (bacteria to spiders) each shares a common building block, which is ? a. presence of nucleus b. cellular structure c. prions d. presence of centrioles e. choose this answer if none of these is a correct choice 86. One of the most prevailing theories for the origins of Life on Earth is that the chemical self-organization of carbon compounds lead to physical chemical complexity which became encapsulated by an amphiphilic bilayer and was probably the progenitor of all subsequent cells. a. true b. false 87. The functional chemical group(s) involved in the disulfide bond is ? a. –PO4 b. –CH3 c . –SH d. –C=O e. none of these 88. The covalent bond is the bond most responsible for a molecules ______ ? a. conformation b. configuration c. electronegativity 89. Solutes that dissolve more readily in water are most likely ? a. hydrophilic b. hydrophobic c. DNA d. size d. fatty acids e. none of these e. none of these 90. In a cell, when considered as a tensegrity structure, the elements that acts as “compression” girders are the ? a. nuclei b. ribosomes c. amino acids d. microtubules e. none of these 91. The following reaction type is classified as a _____ reaction: protein(n) + amino acid1 a. functional group transfer b. hydrolysis < --- > protein(n+1) + H2 O c. redox d. condensation e. none of these 92. The molecule shown to the right is ? a. a zwitterion ion b. a nucleotide c. a beta amino acid d. found only in extremophiles e. none of these 93. The type of chemical bind high-lighted by the shaded area in this molecule is? a. hydrogen bond b. disulfide bond c. peptide bond d. glucagon bond e. none of these is correct 94. The older nomeclature system of the naming of proteins was based upon a protein’s ? a. size b. molecular weight c. solubility in water d. shape e. none of these is a correct choice 95. The native conformation of a protein is the 3D shape which has the lowest free energy expenditure and forms spontaneouly. For proteins this shape can be ? a. globular b. a helix c. a fiber d. choose this answer if it can be all of these 96. The type of protein separation that is based upon the protein binding to charged ligands on a inert matrix, which retards its passage through a glass column is ? a. gel filtration chromatography b. ion exchange chromatography c. electrophoresis d. isolectric focusing e. none ofhtese is correct Bil 255 S 01 – Final Exam – Form 0 – pg 9 97. The number of micromoles of substrate converted to product per min is often referred to as ? a. a unit of enzyme activity b. colorimetry c. Beer-lambert law d. specific acivity e. none ofhtese is correct 98. The NADH made in glycolysis can be moved into the mitochondria by ? a. active transport b. chemiosmosis c. malate shuttle 99. The ATP made in glycolysis is made by ? + a. chemiosmosis b. a H ATPase enzyme d. oxidative phosphorylation e. none of these is correct d. cane shuttle e.none of these c. substrate level phosphorylation th 100. This year marks the 50 anniversary of the tissue culturing of a human cervical cancer cell; that cell is referred to as? a. muscle cell b. Punkinje cell c. Hela cell d. methaogen e. none of these EXTRA CREDIT : 101. The most dynamic teaching duo in cell and molecular biology is ? a. Batman & Robin b. Tom & Jerry c. Butch Cassidy & Sundance Kid e. You must bubble in choice “e” to get credit for this question To our seniors – Congratulations and may you future be productive To all - HAVE A GREAT SUMMER d. Glaser & Mallery ...
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