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67 Cards in this Set
- Front
- Back
1. Viruses that attack bacteria are called |
A. phages |
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2. ___ is the genetic material for all cellular organisms and some viruses. |
B. DNA |
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3. Nucleotides have a phosphate group attached at the ___ carbon atom of the sugar. |
C. 5' |
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4. Watson and Crick developed a model of DNA in which the two strands twist into the shape of a ________________. |
C. double helix |
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5. Because the two strands of a DNA molecule are ________ to each other, either one can be used as a template to reconstruct the other. |
D. complementary |
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6. The synthesis of a growing strand of DNA is carried out by adding nucleotides to the ___ end of an existing strand. |
B. 3' |
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7. DNA consists of two antiparallel strands of nucleotides held together by |
D. hydrogen bonds. |
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8. The method of DNA replication, where each original strand is used as a template to build a new strand, is called the |
B. semiconservative method. |
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9. Which enzyme adds new nucleotides to the end of a growing strand? |
B. polymerase |
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10. Who originally discovered the process of bacterial transformation? |
D. Griffith |
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11. When a mixture of live nonvirulent bacteria and dead virulent bacteria was injected into mice, Griffith unexpectedly found that the injected mice died. He explained this result by suggesting that the nonvirulent bacteria are being |
B. transformed. |
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12. Avery and his coworkers showed that the agent responsible for changing nonvirulent bacteria into virulent bacteria was |
C. DNA. |
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13. Which statement about the Hershey-Chase experiment is false? |
D. The virus-infected bacteria contained radioactive sulfur. |
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14. Based on their experiment with T2 bacteriophages, Hershey and Chase concluded that |
C. DNA functions as the genetic material. |
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15. After attaching to a bacterial cell, a bacteriophage typically |
C. injects DNA into the cell. |
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16. DNA primase |
E. creates a short RNA primer that is complementary to a DNA template. |
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17. As the two strands of DNA are unraveled, which enzyme relieves the strain on the two strands? |
C. DNA gyrase |
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18. Which is not a component of nucleic acids? |
D. sulfur |
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19. The chemical bond connecting one nucleotide with the next along one strand of a DNA molecule is called a |
D. phosphodiester bond. |
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20. Chargaff's rules for the pairing of nitrogen bases is |
B. A = T and G = C. |
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21. Information obtained by Franklin from X-ray crystallography on DNA suggested that it is shaped like a |
A. helix. |
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22. In DNA, complementary nitrogen bases are held together by |
B. hydrogen bonds. |
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23. The two strands of a DNA molecule contain nitrogen bases which are |
C. complementary. |
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24. Replication of DNA is |
D. semiconservative. |
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25. During DNA replication, each new strand begins with a short |
E. RNA primer. |
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26. The lagging strand is replicated with a series of Okazaki fragments and that is why its synthesis is considered to be |
A. discontinuous. |
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27. DNA replication always proceeds by adding new bases to the _______ end of an existing strand. |
C. 3' |
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28. Which of the following statements about DNA replication false? |
D. The newly synthesized DNA is packaged into one nucleus, and the original DNA is packaged into another nucleus. |
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29. The double helix model of DNA structure was proposed by |
A. Watson and Crick. |
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30. Griffith, a British microbiologist, used bacteria and mice to demonstrate the process of transformation. During transformation, |
D. genetic material is transferred from one bacterial cell to another. |
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31. In 1952, Hershey and Chase confirmed Avery's (1944) conclusion that |
B. DNA is the repository for hereditary information. |
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32. If 14% of the nucleotides from a DNA molecule contain the base T, what percent will contain the base G? |
D. 36% |
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33. If a short sequence of DNA is 5' AATTGCCGT 3', its complement is |
C. 3' TTAACGGCA 5'. |
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34. After DNA replication is complete, each strand of the original molecule is bound to a new complementary strand. This process is known as |
C. semiconservative replication. |
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35. The site where the two original DNA strands separate and active replication occurs is called the |
A. replication folk. |
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36. The replisome has two main subcomponents. They are |
E. the primosome and the DNA pol III enzymes. |
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37. During replication, which enzyme unwinds the DNA double helix? |
C. DNA helicase |
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38. What is the correct sequence for DNA replication in E. coli? |
B. initiation, elongation, termination |
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39. Eukaryotic organisms speed up the process of DNA replication by |
D. using multiple origins of replication on each chromosome. |
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40. Endonucleases and exonucleases are enzymes that can remove nucleotides from a polynucleotide chain. An endonuclease removes nucleotides _______ while an exonuclease removes nucleotides _____________. |
C. internally; from the ends of the chain |
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41. During DNA replication, DNA pol III synthesizes the lagging strand in segments, called |
E. Okazaki fragments. |
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42. Who proposed that the structure of DNA is a double helix with two polynucleotide chains running in opposite directions and held together by hydrogen bonding between pairs of nitrogenous bases? |
D. Watson and Crick |
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43. Who demonstrated that phage genetic material is DNA and not protein? |
A. Hershey and Chase |
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44. Who provided X-ray diffraction photographs of purified DNA fibers that suggested a helical structure with a consistent diameter of about 2 nm and a complete helical turn every 3.4 nm? |
C. Franklin |
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45. Who proposed that in any DNA molecule, A =T and G = C? |
B. Chargaff |
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46. In Griffith's experiments, |
C. mice infected with heat-killed virulent bacteria and live nonvirulent bacteria developed pneumonia and died. |
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47. Avery, MacLeod, and McCarty's experiments revealed that the transforming principle had all of the following properties except |
A. its activity was destroyed by treatment with proteases. |
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48. If we think of the DNA double helix as a twisted ladder, what makes up the rungs or steps of the ladder? |
D. purines and pyrimidines |
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49. Deoxyribose has a carbon atom that is not part of the pentose ring. In a nucleotide, what is attached to this carbon? |
B. a phosphate group |
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50. Which of the following DNA sequences is complementary to 5' ATGGTCAGT 3'? |
D. 5' ACTGACCAT 3' |
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51. In DNA, a purine must always pair with a pyrimidine and vice versa in order to ensure that |
A. the distance between the two phosphodiester backbones remains constant. |
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52. During DNA replication, which enzyme removes the RNA primers and then fills in the gap? |
A. DNA pol I |
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53. If a mutation prevented synthesis of the beta subunit of DNA pol III, which would be most affected? |
D. processivity |
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54. Why does DNA pol I carry the number one? |
A. It was the first polymerase isolated from E. coli. |
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55. You are asked to give a classroom demonstration of DNA supercoiling. To do so, you take two different colored pieces of rubber tubing, twist them very tightly and excessively around each other and join the ends of the tubing appropriately. Next, you relieve the supercoiling by breaking one strand and unwinding it. In this demonstration, the breaking and unwinding to relieve the supercoiling simulates the action of |
D. topoisomerases. |
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56. In which cells would you expect to find the highest level of telomerase? |
D. cells that replenish the lining of the gut |
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57. You are asked to participate in a clinical trial for a new drug that can activate telomerase. Which of the following is a likely risk of such a drug? |
B. increased vulnerability to cancer |
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58. After a long week of sunbathing on the beach, what type of DNA damage should you be most concerned about? |
C. thymine dimers |
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59. Xeroderma pigmentosum (XP) is a rare autosomal recessive disorder. Patients with XP exhibit a cellular hypersensitivity to ultraviolet (UV) radiation, a high incidence of skin cancer and premature aging. Based on these clinical characteristics, what is the most likely cause for this disease? |
A. defects in DNA repair |
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60. If a mutation produced helicase that was unable to hydrolyze ATP, DNA replication would be |
A. slowed down. |
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61. Suppose a new form of DNA pol III is discovered that does not require a primer to begin synthesis of a new strand. All other properties of the enzyme remain unchanged. In order to completely replicate all chromosomes in a eukaryotic cell that uses this new enzyme, which of the following would no longer be necessary? |
A. Okazaki fragments |
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62. Suppose a new species of bacterium is discovered. It contains a form of DNA pol III that can add new nucleotides to either the 5' end or the 3' end of an existing strand. All other properties of the enzyme remain unchanged. How would DNA replication in these bacteria differ from normal replication? |
A. both new strands could be synthesized continuously |
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63. If 16% of the nucleotides in one strand of a DNA molecule contain the base G, what percent of the nucleotides on the complementary strand will also contain the base G? |
E. Impossible to determine from the information given. |
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64. You decide to repeat the Meselson-Stahl experiment, except this time you plan to grow the cells on light 14N medium for many generations and then transfer them to heavy 15N medium and allow them to grow for 2 additional generations (2 rounds of DNA replication). If the conservative model of DNA replication is correct, what is the expected distribution of DNA in the density gradient after one round of replication? |
D. One band of light density and one band of heavy density |
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65. You decide to repeat the Meselson-Stahl experiment, except this time you plan to grow the cells on light 14N medium for many generations and then transfer them to heavy 15N medium and allow them to grow for 2 additional generations (2 rounds of DNA replication). If the semiconservative model of DNA replication is correct, what is the expected distribution of DNA in the density gradient after two rounds of replication? |
C. One band of intermediate density and one band of heavy density |
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67. Genetic analysis indicates that an unknown organism contains a gene that codes for a defective form of telomerase. Based on this information alone, you can conclude that this organism |
B. is eukaryotic. |
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68. Genetic analysis indicates that you have a gene that codes for a defective form of photolyase. This puts you at increased risk for developing |
A. skin cancer. |