3/16/2021 mid-term exam: PHY4274 Radiation Biophysics https://canvas.cityu.edu.hk/courses/40714/quizzes/40492?preview=1 1/4 Quiz Type Points Assignment Group Shuffle Answers Time Limit Multiple Attempts View Responses One Question at a Time Require Respondus LockDown Browser Required to View Quiz Results Lock Questions After Answering mid-term exam This is a preview of the draft version of the quiz Graded Quiz 21 Assignments Yes 60 Minutes No No Yes No No No Due For Available from Until Mar 3 at 1:10pm Everyone Mar 3 at 12:01pm Mar 3 at 1:15pm Correct answers are hidden. Score for this quiz: 21 out of 21 Submitted Mar 16 at 8:43pm This attempt took 6 minutes. Published Preview Edit This exam contains 16 questions. Each question is a multi-choices or multi-answers question. You should finish them in 60 min. Preview 1 / 1 ptsQuestion 1 Which of the following aberrations was/were suitable marker(s) to measure the radiation doses exposed to survivors of the atomic bomb attacks in Japan after 50 years? Deletion Ring chromosome Symmetric translocation Dicentric chromosome Chromatid bridge 1 / 1 ptsQuestion 2 Two models have been developed to explain the shapes of cell survival curves: the linear-quadratic model and the multi-target single-hit model. In which respect, the multi-target single-hit model outperforms the linear-quadratic model? The multi-target single-hit model works better in the large-dose regime The multi-target single-hit model can explain the bending of survival curves The multi-target single-hit model can explain the final slopes of survival curves The multi-target single-hit model works better in the small-dose regime 3/16/2021 mid-term exam: PHY4274 Radiation Biophysics https://canvas.cityu.edu.hk/courses/40714/quizzes/40492?preview=1 2/4 1 / 1 ptsQuestion 3 Which of the following statements is/are true about the multi-target single-hit model? If one target is hit, the cell is considered to be killed If a target is hit more than one time, this target is considered to be killed If a target is hit once, this target is considered to be killed If all targets are hit, the cell is considered to be killed 4 / 4 ptsQuestion 4 Suppose that a tumor consists of 10 cells. The effective cell surviving curve has no shoulder and D = 8 Gy. How much dose is required to achieve a tumor control probability of 99%? 10 10 80 Gy 100 Gy 96 Gy 120 Gy 1 / 1 ptsQuestion 5 Which of the following repair paths is/are error-prone and may lead to cell death? Mismatch repair Base excision repair Nucleotide excision repair Homologous recombination repair Non-homologous end joining 1 / 1 ptsQuestion 6 X-ray can damage DNA molecules via direct and indirect actions. What is the fraction of the damages from the indirect action out of all damages by X-ray? 2/3 3/4 1/3 1/2 1 / 1 ptsQuestion 7 DNA in cells is much more resistant to radiation damages than free DNA, because Cells contains free radical scavengers. The temperature in cells is higher than environment temperature. DNA in cells contains more CG content. Proteins around DNA in cells provide physical protection to DNA. 3/16/2021 mid-term exam: PHY4274 Radiation Biophysics https://canvas.cityu.edu.hk/courses/40714/quizzes/40492?preview=1 3/4 1 / 1 ptsQuestion 8 In the linear-quadratic model, the quadratic term dominates when the radiation dose is Less than β Less than α Less than α/β Greater than α/β 1 / 1 ptsQuestion 9 Which of the following reasons is/are responsible for that DNA is the major target of radiation-induced cell death? Chemical groups in DNA are easier to absorb radiation. DNA is a very long molecule. Handling long DNA during cell division is sophisticated. DNA has a double helix structure. 1 / 1 ptsQuestion 10 When a dicentric chromosome occurs in a cell, what is the minimum number of single-strand DNA breaks that have been experienced by this cell? 1 3 8 2 4 1 / 1 ptsQuestion 11 Which of the following statements is/are correct regarding single-strand DNA break? Single-strand DNA breaks are more common than double-strand DNA breaks. Single-strand DNA breaks sometimes cause double-strand DNA breaks. Single-strand DNA breaks are easier to be correctly repaired after DNA replication. Single-strand DNA breaks can never lead to cell death because they can always be repaired. 1 / 1 ptsQuestion 12 Which one of the following biological processes dramatically enhances the damage by the ring chromosome? DNA transcription DNA packaging into nucleosomes sister chromatid exchange 3/16/2021 mid-term exam: PHY4274 Radiation Biophysics https://canvas.cityu.edu.hk/courses/40714/quizzes/40492?preview=1 4/4 DNA packaging into chromatin fiber DNA translation 1 / 1 ptsQuestion 13 Which of the following radiation(s) is/are directly ionizing radiations? Electron X-ray Neutron Proton 1 / 1 ptsQuestion 14 What is the time scale of the lifetime of ion radical H O induced by ionizing radiations?3 + 10^-9 sec 10^-12 sec 10^-15 sec 10^-10 sec 1 / 1 ptsQuestion 15 Which of the following statements is/are true? Most regions of human genome are non-coding DNA The number of genes in human genome is larger than the one in wheat. The DNA region corresponding to actively transcribing genes are more radioresistant DNA fragments induced by radiations usually have lengths multiple times of 20 nm 3 / 3 ptsQuestion 16 Suppose that a tumor consists of 10 cells. The effective cell surviving curve has no shoulder and D = 5 Gy. How much dose is required to achieve a tumor control probability of 99%? 10 0 96 Gy 138 Gy 115 Gy 60 Gy Quiz Score: 21 out of 21
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