Deck 7: Molecular and Cellular Radiation Biology

Question 1

Which of the following statements is true concerning patients who receive radiation exposure from a routine radiographic procedure such as a chest x-ray?

A)Patients are expected to sustain appreciable damage to either the blood or the blood-forming organs as a consequence of the examination.
B)Patients are not expected to sustain appreciable damage to either the blood or the blood-forming organs as a consequence of the examination.
C)Patients are expected to sustain some damage to either the blood or the blood-forming organs as a consequence of the examination.
D)Patients are expected to sustain total damage to either the blood or the blood-forming organs as a consequence of the examination,resulting in fatality.

Answer 1

Patients are not expected to sustain appreciable damage to either the blood or the blood-forming organs as a consequence of the examination.

Question 2

The normal white blood cell count for an adult ranges from

A)1000 to 5000/mm³ of blood.
B)3000 to 6000/mm³ of blood.
C)5000 to 10,000/mm³ of blood.
D)7000 to 15,000/mm³ of blood.

Answer 2

5000 to 10,000/mm³ of blood.

Question 3

Which of the following is/are considered low-LET radiation(s)?
1)X-rays
2)Alpha particles
3)Gamma rays

A)1 only
B)2 only
C)1 and 3 only
D)2 and 3 only

Answer 3

1 and 3 only

Question 4

The term apoptosis is synonymous with

A)programmed cell death.
B)meiosis.
C)mitosis.
D)point mutation.

Question 5

A periodic blood count is not recommended as a method for monitoring occupational radiation exposure because
1)biologic damage from ionizing radiation cannot be determined from a blood test.
2)biologic damage has already been sustained when an irregularity is seen in the blood count.
3)a traditional blood count is a relatively insensitive test that is unable to indicate exposures of less than 10 cGy.

A)1 only
B)2 only
C)3 only
D)2 and 3 only

Question 6

When LET increases,the chance of producing a significant biologic response in the radiosensitive DNA macromolecule

A)grows.
B)decreases considerably.
C)decreases slightly.
D)remains constant,not increasing or decreasing.

Question 7

Direct action may occur after exposure to any type of radiation,but it is much more likely to happen after exposure to

A)low-LET radiation such as x-rays.
B)low-LET radiation such as gamma rays.
C)high-LET radiation such as alpha particles.
D)nonionizing radiation such as microwaves.

Question 8

Which of the following curves illustrates the radiation sensitivity of a particular type of cell?

A)Cell specialization curve
B)Cell extrapolation curve
C)Dose-response curve
D)Cell survival curve

Question 9

A biologic reaction is produced by 4 Gyt of a test radiation.It takes 16 Gyt of 250-kVp x-rays to produce the same biologic reaction.What is the relative biologic effectiveness (RBE)of the test radiation?

A)2
B)4
C)8
D)12

Question 10

The radiation dose required to produce mitotic death is

A)less than the dose needed to produce apoptosis in slowly dividing cells or nondividing cells.
B)more than the dose needed to produce apoptosis in slowly dividing cells or nondividing cells.
C)the same as the dose needed to produce apoptosis in slowly dividing cells or nondividing cells.
D)nonexistent because mitotic death cannot be produced in slowly dividing cells or nondividing cells as a result of exposure to ionizing radiation.

Question 11

Because the master molecule is unique in any given cell,no similar molecules in the cell are available to replace it; if a critical location on the master molecule is a target receiving multiple hits from ionizing radiation,the master molecule may be inactivated.If this occurs,what is the consequence for the affected cell?

A)Loss of all intracellular fluid
B)Increased pressure on the cell membrane leading to immediate rupture
C)Disruption of cell chemistry only
D)Normal cell function will cease,and the cell will die.

Question 12

Which of the following humans is most radiosensitive?

A)A mature adult
B)An embryo-fetus during the first trimester of pregnancy
C)A fetus during the third trimester of gestation
D)A 5-year-old child

Question 13

Because the genetic information to be passed on to future generations is contained in the strict sequence of nitrogenous bases,the loss or change of a base in the DNA chain represents a (an)

A)aneuploidy.
B)bleb.
C)covalent cross-link.
D)mutation.

Question 14

One micron (mm)= __________.

A)10^-6 m
B)10⁺⁶ m
C)10^-3 m
D)10⁺³ m

Question 15

When free radicals previously produced by the interaction of radiation with water molecules act on a molecule such as DNA,the damaging action of ionizing radiation is indirect in the sense that the radiation is not the immediate cause of injury to the macromolecule.What is the immediate cause of this damage?

A)Excitation of the atoms of the biologic macromolecules
B)Enzymes released from biologic macromolecules
C)The recombining of a positively charged water molecule with an electron
D)The free radicals produced by the interaction of radiation with water molecules

Question 16

OH* + OH* = __________.

A)H₂O
B)HOH+
C)HOH-
D)H₂O₂

Question 17

Which of the following groups of cells is least radiosensitive?

A)Adult nerve cells
B)Nerve cells in an embryo-fetus
C)Lymphocytes
D)Immature spermatogonia

Question 18

Based on current data,which of the following would be considered a safe radiation dose for the gonads of both males and females?

A)5 Gyt
B)3 Gyt
C)1 Gyt
D)0 Gyt

Question 19

Which of the following groups of cells is most radiosensitive?

A)Lymphocytes
B)Adult nerve cells
C)Erythrocytes
D)Muscle cells

Question 20

Which of the following gonadal radiation doses may cause permanent sterility in a male human?

A)0.01 Gyt
B)1.0 Gyt
C)2.0 Gyt
D)5.0 or 6.0 Gyt

Question 21

Neutrophils play an important role in

A)initiating the circulation of blood through the human body.
B)initiating blood clotting.
C)fighting infection.
D)preventing hemorrhage.

Question 22

Which of the following tissues contain cells that do not divide?
1)Epithelial tissue
2)Muscle tissue
3)Nervous tissue in an adult

A)1 and 2 only
B)1 and 3 only
C)2 and 3 only
D)1,2,and 3

Question 23

If bone marrow cells have not been destroyed by exposure to ionizing radiation,they can

A)become insensitive to future exposures from ionizing radiation.
B)overpopulate and become radioresistant.
C)remain in circulating blood indefinitely.
D)repopulate after a period of recovery.

Question 24

Which of the following is a scavenger type of white blood cell that fights bacteria?

A)Granulocytes
B)Lymphocytes
C)Neutrophils
D)Thrombocytes

Question 25

The radiosensitivity of ova

A)remains constant throughout the lifetime of the germ cell.
B)varies considerably throughout the lifetime of the germ cell.
C)varies slightly throughout the lifetime of the germ cell.
D)is insignificant because the germ cell is not radiosensitive.