Chat with AIExam 12: DNA Replication and Recombination
You have discovered a special dye that reveals the position of recombination sites on meiotic chromosomes. You use this dye to count the number of recombination sites and then compare this to the number of genetic exchanges that you can detect by looking at the segregation of markers across the genome. You find many more recombination sites as compared to genetic exchanges. Explain this result.
(42) 
Answered by Examlex AI CopilotThe discrepancy between the number of recombination sites and the number of genetic exchanges can be explained by the occurrence of multiple recombination events at a single site. During meiosis, homologous chromosomes undergo genetic recombination, where segments of DNA are exchanged between maternal and paternal chromosomes. This process creates new combinations of genetic material and contributes to genetic diversity.
The special dye that reveals recombination sites allows for the direct visualization of these events on meiotic chromosomes. However, it is possible for multiple recombination events to occur at the same physical location on a chromosome, resulting in the detection of more recombination sites than the actual number of genetic exchanges.
Additionally, the resolution of the dye may allow for the detection of smaller recombination events that do not result in observable genetic exchanges. These smaller events may not lead to detectable changes in the segregation of genetic markers across the genome, leading to a discrepancy between the number of recombination sites and genetic exchanges.
Overall, the discrepancy between the number of recombination sites and genetic exchanges can be attributed to the complexity of meiotic recombination and the limitations of detection methods. It highlights the intricacies of genetic recombination and the need for comprehensive approaches to studying these processes.
If ribonucleotides were depleted from a cell during S phase, how would DNA synthesis be affected? (Ignore energetic considerations.)
(35) 
VerifiedE
Which of the following enzyme and function pairs is INCORRECTLY matched?
(40) VerifiedC
Discuss the main differences in the initiation of recombination proposed by the Holliday model and the double-stranded-break model.
(32) Which of the following is a protein that facilitates the termination of replication in E. coli?
(39) DNA primase requires a _____ template and _____ nucleotides to initiate primer synthesis.
(36) Explain the effect on DNA replication of mutations that destroy each of the following activities in DNA polymerase. Also, for each kind of mutation, how might you detect the effect in an in vitro replication reaction?
a. 5'to 3' polymerase
b. 5'to 3' exonuclease
c. 3' to 5' exonuclease
(37) You are studying a new virus with a DNA genome of 12 Kb. It can synthesize DNA at a rate of 400 nucleotides per second. If the virus uses rolling-circle replication, how long will it take to replicate its genome?
(44) Are Okazaki fragments formed on the leading strand during DNA replication? Explain your answer.
(43) (a) Explain the significance of telomerase in cells of the germ line. (b) Explain the significance of telomerase in cancer cells.
(27) Suppose that some cells are grown in culture in the presence of radioactive nucleotides for many generations so that both strands of every DNA molecule include radioactive nucleotides. The cells are then harvested and placed in new Moderate with nucleotides that are not radioactive so that newly synthesized DNA will not be radioactive. What proportion of DNA molecules will contain radioactivity after two rounds of replication?
(33) Which of the following statements is TRUE of DNA polymerases of eukaryotic cells?
(38) You are studying a new virus with a DNA genome of 12 Kb. It can synthesize DNA at a rate of 400 nucleotides per second. If the virus uses theta replication, how long will it take to replicate its genome?
(34) During DNA replication, the synthesis of the new strand requires the addition of a new dNTP to the 3ʹ-OH group of the growing nucleotide strand by DNA polymerase. Which of the following provides the energy needed for this step?
(25) You discover a drug that specifically inhibits DNA synthesis. You apply the drug to yeast cells after S phase but before prophase of meiosis. You find a drastic reduction in recombination in the meiotic products. How can you explain this?
(29) Which of the following does NOT utilize bidirectional replication?
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