Nothing Special   »   [go: up one dir, main page]
Scribd Logo
Upload

Welcome to Scribd!

  • 180 views

    Radiation Biology Questions

    Uploaded by

    Roxy Marie Chan
    1. Ionizing radiation can induce DNA double-strand breaks, which are more difficult for cells to repair than single-strand breaks. 2. Broken DNA strands can recombine and rejoin incorrectly, leading to chromosomal aberrations like translocations or deletions. 3. Chromosomal aberrations are divided into chromosome and chromatid types depending on whether they occur before or after DNA duplication in the cell cycle. These aberrations can cause cell death, mutation, or carcinogenesis.

    Copyright:

    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd

    Radiation Biology Questions

    Uploaded by

    Roxy Marie Chan
    180 views2 pages
    1. Ionizing radiation can induce DNA double-strand breaks, which are more difficult for cells to repair than single-strand breaks. 2. Broken DNA strands can recombine and rejoin incorrectly, leading to chromosomal aberrations like translocations or deletions. 3. Chromosomal aberrations are divided into chromosome and chromatid types depending on whether they occur before or after DNA duplication in the cell cycle. These aberrations can cause cell death, mutation, or carcinogenesis.

    Original Description:

    test

    Original Title

    Radiation biology questions

    Copyright

    © © All Rights Reserved

    Available Formats

    DOCX, PDF, TXT or read online from Scribd

    Did you find this document useful?

    Is this content inappropriate?

    1. Ionizing radiation can induce DNA double-strand breaks, which are more difficult for cells to repair than single-strand breaks. 2. Broken DNA strands can recombine and rejoin incorrectly, leading to chromosomal aberrations like translocations or deletions. 3. Chromosomal aberrations are divided into chromosome and chromatid types depending on whether they occur before or after DNA duplication in the cell cycle. These aberrations can cause cell death, mutation, or carcinogenesis.

    Copyright:

    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd
    Download as docx, pdf, or txt
    180 views2 pages

    Radiation Biology Questions

    Uploaded by

    Roxy Marie Chan
    1. Ionizing radiation can induce DNA double-strand breaks, which are more difficult for cells to repair than single-strand breaks. 2. Broken DNA strands can recombine and rejoin incorrectly, leading to chromosomal aberrations like translocations or deletions. 3. Chromosomal aberrations are divided into chromosome and chromatid types depending on whether they occur before or after DNA duplication in the cell cycle. These aberrations can cause cell death, mutation, or carcinogenesis.

    Copyright:

    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd
    Download as docx, pdf, or txt
    of 2

    Chapter 1 - physics and chemistry of radiation

    1. What is the difference between X-rays and gamma 7. A free radical is:
    rays?
    a. Any charged particle.
    a. X-rays are produced extranuclearly whereas b. An atom or molecule with an unpaired
    gamma rays are produced in nuclear decays. electron in the outer shell.
    b. X-rays have higher energies than gamma rays. c. An atom with an even number of electrons.
    c. gamma rays are produced by bremsstrahlung. d. A chemically stable atom.
    d. X-rays and gamma rays interact with matter
    differently.
    8. The main interaction process(es) of neutrons in
    biologic matter are:
    2. What is the main source of natural background
    a. Magnetic scattering.
    radiation?
    b. Coulomb scattering by orbital electrons.
    a. Electrons. c. Fission.
    b. X-rays. d. Elastic and inelastic scattering by nuclei.
    c. Neutrons.
    d. Alpha-particles.
    9. All types of radiation can induce biologic effects by
    direct or indirect action.
    3. Which photon processes are dominant in the
    context of diagnostic radiology? a. True.
    b. False.
    a. Compton scattering and photoelectric effect.
    b. Photoelectric effect and pair production.
    c. Compton scattering and pair production. 10. What is the main reason for the difference in
    d. Compton and Rayleigh scattering. biologic effects caused by neutrons and photons?

    a. The energy of the radiation.


    4. The mass absorption coefficient for Compton b. The fact that the charged particles produced
    scattering is independent of the atomic number (Z) of by neutrons are, for the most part, positively
    the absorber whereas the mass absorption coefficient charged.
    for photoelectric effect depends strongly on Z. c. The density of ionization.
    d. The fact that neutrons can interact with
    a. True.
    nuclei.
    b. False.

    5. Direct action of radiation is the dominant process


    for:

    a. X-rays.
    b. Neutrons and alpha particles.
    c. Electrons.
    d. Gamma rays.

    6. Which of the following statements is true?

    a. Indirect action can be modified by protectors


    or sensitizers.
    b. Direct action can be modified by protectors or
    sensitizers.
    CHAPTER 2- DNA STRAND BREAKS AND CHROMOSOMAL ABERRATIONS
    1. What is the most important lesion produced in chromosomal 7. Following exposure to radiation, some of the chromatin strands
    DNA by exposure to ionizing radiation? are broken. Broken ends are "sticky" and can join to other broken
    "sticky" ends. Which of the following statements is false?
    a. A break on one DNA strand ('single-strand break').
    b. Well-separated breaks on both DNA strands. a. Broken ends of the same chromatin can recombine to
    c. Breaks on both DNA strands which are opposite each restore the original structure of the chromosome.
    other or separated by only a few bases ('double-strand b. The broken end of one chromatin strand can join to the
    break'). broken end of another chromatin strand (which leads to
    d. Multiple breaks on the same DNA strand. a chromosomal aberration)
    c. Broken ends fail to rejoin (which leads to a chromosomal
    aberration).
    2. When cells are irradiated with x-rays, double-strand breaks d. A broken end of a chromatin strand joins to an unbroken
    occur at a rate of about 5% in comparison to single-strand breaks. end of another chromatin strand.

    a. True.
    b. False. 8. The chromosome material is duplicated at:

    a. prophase.
    3. Which of the following statements is correct? b. metaphase.
    c. interphase.
    a. Double-strand breaks can be repaired by homologeous d. anaphase.
    recombination or nonhomologous recombination.
    b. Nonhomologous recombination is error-free. 9. Which of the following statements is false?
    c. Homologous recombination occurs often in mammalian a. Chromosomal aberrations are divided into
    cells "chromosome aberrations" and "chromatid
    d. Homologous recombination accounts for many of the aberrations".
    premutagenic lesions induced in the DNA of human cells b. Chromosome aberrations are caused by irradiation that
    by ionizing radiation. takes place before the DNA is duplicated.
    c. Chromatid aberrations are caused by irradiation that
    takes place after the DNA is duplicated.
    4. Which of the following statements is false? d. Chromatid aberrations involve identical breaks in the
    two strands of chromatin of the duplicated DNA
    a. 95% of the energy deposition of x-rays and gamma rays structure.
    occurs in spurs (which have a diameter of about 4 nm
    and involve 3 ion pairs on average).
    b. Spurs and blobs are equally frequent in the case of high 10. Which of the following statements is false?
    energy gamma rays.
    c. Blobs have a diameter of about 7 nm and contain 12 ion a. Chromosomal aberrations can lead to cell killing,
    pairs on average. mutation or carcinogenesis.
    d. As spurs and blobs have a diameter similar to the DNA b. The ring aberration and the dicentric aberration are
    diameter, complex lesions occur when they overlap with chromatid aberrations that are lethal to the cell.
    the DNA helix ('locally multiply damaged site'). c. The anaphase bridge is a chromosomal aberration that is
    lethal to the cell.
    d. Symmetric translocations and small deletions are
    5. The D0 dose is the dose that: chromosomal aberrations that are not lethal but
    a. induces an average of one lethal event per cell and
    they can cause malignancies.
    leaves 37% still viable.
    b. leaves 50% of all cells viable.
    11. Which of the following statements is correct?
    c. kills all cells.
    d. kills 30% of all cells. a. The total-body dose in exposed persons can be
    evaluated by taking blood samples and scoring the
    frequency of dicentrics and rings in the lymphocytes one
    6. Chromosomal aberrations are caused by: year after exposure.
    b. The total-body dose in exposed persons can be
    a. single-strands breaks. evaluated by taking blood samples and scoring the
    b. double-strand breaks, i.e. breaks that cause the frequency of translocations in the lymphocytes up to
    chromatin to snap into two pieces. several years after exposure.
    c. single-strand or double-strand breaks.

    You might also like