BI110 Lecture Notes - Lecture 8: Rna World, Dna Replication, Deoxyribose
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QUESTION 1. Compared to eukaryotic genomes, only prokaryotic genomes:
A. contain DNA organized by histones. |
B. contain usually one, circular chromosome. |
C. contain plasmid DNA. |
D. have chromosomes contained in a nucleus. |
QUESTION 2. Azathioprine is a drug that may be prescribed to transplant recipients to reduce the chance of tissue rejection reactions. In its active state, it acts as a purine analogue, inhibiting DNA biosynthesis. This means that 6-mercaptopurine will be inserted in place of a purine containing nucleotides during DNA replication. Given this drug's mode of action, you would expect it to be incorporated into DNA in place of:
A. nucleotides containing guanine or cytosine. |
B. nucleotides containing adenine or thymine. |
C nucleotides containing adenine or guanine. |
D. nucleotides containing guanine nucleotide or uracil. |
QUESTION 3. RNA is distinguished from DNA because only RNA:
A. typically exists as a single-stranded molecule. |
B. has a 3' to 5' directionality. |
C. is composed of nucleotides that contain the sugar deoxyribose. |
D. is composed of nucleotides that contain the nitrogen bases T, C, G, and A. |
QUESTION 4. How are RNA nucleotides different from DNA nucleotides? To be marked correct, you'll need to select all true statements, as there may be more than one correct answer.
A. RNA nucleotides do not contain thymine. |
B. RNA nucleotides use the sugar ribose, while DNA nucleotides do not. |
C. RNA nucleotides lack phosphate. |
D. RNA nucleotides incorporate pyrimidine nitrogen bases, while DNA nucleotides only incorporate purine nitrogen bases. |
1. | In addition to identifying the genetic material, the experiments of Avery, MacLeod, and McCarty with different strains of Streptococcus pneumoniae demonstrated that | ||||||||||
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2. | In order to show that DNA in cell extracts is responsible for genetic transformation in Streptococcus pneumoniae, important corroborating evidence should indicate that _______ also destroy transforming activity. | ||||||||||
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3. | Based on what you have learned about the experiments conducted by Griffith and Avery and colleagues with bacteria, which of the following would result in transformation of living R cells? | ||||||||||
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4. | A-T base pairs in a DNA double helix | ||||||||||
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5. | If 23 percent of the bases in a sample of double-stranded DNA are adenine, what percentage of the bases are uracil? | ||||||||||
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6. | The uniform diameter of the DNA structure provides evidence for | ||||||||||
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7. | If a sequence of one strand of DNA is 5â²-TGACTATC-3â², what is the complementary strand? | ||||||||||
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8. | What structural aspect of the DNA facilitates dissociation of the two DNA strands for replication? | ||||||||||
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9. | If the MeselsonâStahl density gradient experiment had resulted in two bands of DNA molecules after only one round of replication, one containing only 15N and the second only 14N, this result would have indicated that replication was | ||||||||||
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10. | The nucleoside analogue acyclovir, which is used to treat herpes simplex virus (HSV) infections, lacks a 3â² hydroxyl group (âOH). Predict what will happen if the host cell DNA polymerase incorporates a molecule of acyclovir into an elongating strand of HSV DNA. | ||||||||||
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11. | Which of the following does not demonstrate the stability of the DNA double helix? | ||||||||||
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12. | What effect would a primase inhibitor have on DNA replication? | ||||||||||
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13. | To replicate their DNA in a timely manner, most eukaryotic chromosomes | ||||||||||
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14. | Which statement about DNA replication is false? | ||||||||||
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15. | In many eukaryotes, there are repetitive sequences called telomeres at the ends of chromosomes. After successive rounds of DNA replication, the _______ strand becomes shorter. In some cells, an enzyme called _______ repairs the shortened strand. | ||||||||||
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16. | A researcher studies normal human fibroblast cells. They can be maintained in culture but die off after about 30 cell generations. Unexpectedly, a colony of cells continues to survive and divide past 30 generations. Which scenario is most likely true for these cells? | ||||||||||
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17. | If DNA polymerase III introduces an incorrect nucleotide, what is the first corrective action made by the DNA repair system? | ||||||||||
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18. | Choose the correct order of the following four events in the excision repair of DNA: (1) Base-paired DNA is made complementary to the template. (2) Damaged bases are recognized. (3) DNA ligase seals the new strand to existing DNA. (4) Part of a single strand is excised. | ||||||||||
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19. | Six complete cycles of PCR should result in a _______-fold increase in the amount of DNA. | ||||||||||
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20. | When double-stranded DNA is heated to temperatures above 90°C, it denatures. Denaturation is a process that | ||||||||||
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