3 radiation biology Flashcards
Qn: Which of the following is the correct sequence of stages during mitosis?
A) Prophase → Metaphase → Telophase → Anaphase
B) Prophase → Metaphase → Anaphase → Telophase
C) Metaphase → Prophase → Telophase → Anaphase
D) Telophase → Anaphase → Prophase → Metaphase
B
Which of the following phases is most resistant to DNA damage, leading to an reduced risk of cell death if exposed to radiation?
A) Late G1 phase
B) Early G1 phase
C) Mitosis (M phase)
D) Synthesis (S phase)
D
Question: Which of the following is true regarding the early or acute effects of radiation?
A) They primarily manifest in slowly proliferating tissues such as the lungs and kidneys.
B) Acute effects are influenced by dose, fractionation timing, and the ability of stem cells to repair damage.
C) Late effects of radiation develop rapidly within days or weeks post-irradiation.
D) High-dose radiation always leads to irreversible damage, regardless of stem cell proliferation.
B
Question: Which of the following statements about DNA damage caused by radiation is correct?
Single-strand breaks (ss) are typically more detrimental than double-strand breaks (ds) because they are harder to repair.
B) Double-strand breaks (ds) in DNA are more lethal and harder to repair compared to single-strand breaks (ss), leading to higher risk of cell death.
C) Single-strand breaks (ss) are not considered significant damage and have no impact on the cell’s survival.
D) Double-strand breaks (ds) occur more frequently than single-strand breaks (ss) after radiation exposure
B
Question: Which of the following statements is true regarding the effects of radiation on cells?
A) Reproductive death occurs at doses between 1-10 Gy and results in the loss of a cell’s ability to reproduce, without immediate cell death.
B) Instant cell death is caused by high doses (~100 Gy) of X-rays or gamma rays and results in severe disruption of cellular form and structure.
C) Apoptosis occurs after a single division and requires high radiation doses.
D) Mitotic delay requires doses of 5 Gy or more to interfere with cell division and cause death
A
Which of the following is true of the cell cycle?
Mitosis involves: Prophase, Metaphase, Anaphase, Telophase
It consists of the phases G1, S, G2 , Mitosis, Cytokinesis
The G1 phase: cell increases in size, biosynthetic activity (protein/enzyme production) prepares for DNA replication.
It consists of 4 check points: G1, G2, Metaphase, G0
B
Which of the following is/are false?
The M phase is most sensitive to radiation injury
The S-phase is the most sensitive to radiation injury as the chromosomes are condensed.
Actively dividing tissues like the lung and kidney respond early to the effects of radiation
In late responding tissue, the effect emerge months or years after radiation exposure and include effects like necrosis, tissue atrophy, vascular damage.
“Consequential late effect” occurs when an early reaction in a rapidly proliferating tissue may persist as a chronic injury
B, C
The M-phase is the most sensitive to radiation injury as the chromosomes are condensed. – The S phase is the most resistant.
Actively dividing tissues like the skin, intestinal epithelium, bone marrow respond early to the effects of radiation
Which of the following best describes apoptotic cell death?
It is exhibited by most non-haemapoeitic cell lineages in response to ionizing radiation.
Form of programmed cell death – expressed in embryonal and haematopoietic cells
Tends to occur in either first cell division after irradiation
Involved damage to particular genes on the chromosomal level
Form of programmed cell death – expressed in embryonal and haematopoietic cells
- Which of the following is/are true of the linear energy transfer?
Average amount of energy deposited in the tissue (absorber) close to the particle track per unit path time - expressed as eV or KeV per μs
The average amount of energy deposited in the tissue (absorber) close to the particle track per unit path length - expressed as eV or KeV per μm
It can be expressed by this equation:
Dose in Gy of 250kV x-rays required to produce effect X/ Dose in Gy of test radiation required to produce effect X
LET is proportional to the charge of a particle and particles kinetic energy.
High LET particles are more damaging to tissue locally
B and E
The average amount of energy deposited in the tissue (absorber) close to the particle track per unit path length - expressed as eV or KeV per μm
High LET particles are more damaging to tissue locally
C is the RBE
