Radiobiology MCQs

What is radiobiology primarily concerned with?
- A) The study of radioactive materials
- B) The effects of radiation on living organisms
- C) The development of radiation therapies
- D) The physics of radiation
Which type of radiation has the highest biological effectiveness?
- A) Gamma rays
- B) Alpha particles
- C) Beta particles
- D) X-rays
What term describes the total energy absorbed by tissue from radiation exposure?
- A) Dose rate
- B) Absorbed dose
- C) Effective dose
- D) Equivalent dose
What is the primary target for radiation damage in cells?
- A) Mitochondria
- B) DNA
- C) Cytoplasm
- D) Cell membrane
Which process involves programmed cell death in response to radiation damage?
- A) Apoptosis
- B) Necrosis
- C) Mitosis
- D) Differentiation
What is the significance of the linear energy transfer (LET) in radiobiology?
- A) It measures the speed of radiation
- B) It indicates the amount of energy transferred per unit length
- C) It quantifies the total radiation exposure
- D) It measures the ionization potential
Which of the following best describes stochastic effects of radiation?
- A) They have a threshold dose
- B) They increase in probability with dose
- C) They cause immediate damage
- D) They are deterministic effects
What is the purpose of a dose-response curve in radiobiology?
- A) To measure radiation levels in the environment
- B) To show the relationship between dose and biological effect
- C) To predict radiation therapy outcomes
- D) To assess radiation exposure in patients
Which type of radiation damage involves direct hits to the DNA molecule?
- A) Indirect damage
- B) Direct damage
- C) Secondary damage
- D) Tertiary damage
What is the role of oxygen in radiation therapy?
- A) It enhances radiation production
- B) It increases the effectiveness of radiation damage
- C) It acts as a shielding agent
- D) It reduces side effects
Which type of radiation therapy uses high-energy beams to destroy cancer cells?
- A) External beam radiation therapy
- B) Brachytherapy
- C) Radioisotope therapy
- D) Photodynamic therapy
What is the dose at which 50% of the population would experience a specific effect called?
- A) Threshold dose
- B) LD50
- C) ED50
- D) Reference dose
Which cellular repair mechanism is primarily responsible for fixing single-strand DNA breaks?
- A) Homologous recombination
- B) Base excision repair
- C) Nucleotide excision repair
- D) Non-homologous end joining
What factor does NOT affect tissue radiosensitivity?
- A) Cell cycle phase
- B) Color of the tissue
- C) Oxygen levels
- D) Cell differentiation
Which type of radiation is most commonly used in cancer treatment?
- A) Alpha particles
- B) X-rays
- C) Beta particles
- D) Neutron radiation
What is the primary effect of radiation on stem cells?
- A) Inhibition of proliferation
- B) Enhanced differentiation
- C) Increased survival
- D) Cell migration
What type of cellular change is characterized by uncontrolled cell division due to radiation exposure?
- A) Carcinogenesis
- B) Apoptosis
- C) Differentiation
- D) Necrosis
Which of the following best describes the term “radiation hormesis”?
- A) Radiation is always harmful
- B) Low doses of radiation may have beneficial effects
- C) Radiation effects are cumulative
- D) High doses are safe
What type of radiation exposure is most likely to lead to deterministic effects?
- A) High dose exposure
- B) Low dose exposure
- C) Chronic exposure
- D) Intermittent exposure
What is the main consequence of radiation-induced double-strand breaks in DNA?
- A) Cell death
- B) Increased cell growth
- C) Enhanced DNA repair
- D) No effect
Which of the following tissues is least affected by radiation?
- A) Lymphoid tissue
- B) Bone marrow
- C) Skin
- D) Muscle tissue
What is the term for the phenomenon where radiation exposure leads to changes that can be passed to future generations?
- A) Epigenetic changes
- B) Genetic mutations
- C) Acquired traits
- D) Phenotypic changes
Which factor is crucial in determining the effectiveness of radiation therapy?
- A) Dose rate and fractionation
- B) Type of radiation used
- C) Duration of exposure
- D) Distance from the radiation source
What is the main advantage of using radioprotectors?
- A) They enhance tumor growth
- B) They reduce radiation damage to healthy tissues
- C) They increase side effects
- D) They are used for imaging
Which process is critical for the repair of double-strand breaks in DNA?
- A) Homologous recombination
- B) Base excision repair
- C) Nucleotide excision repair
- D) Transcription
What is the effect of radiation on the immune system?
- A) Immunosuppression
- B) Enhanced immunity
- C) No effect
- D) Increased white blood cell count
Which type of ionizing radiation is most commonly found in natural background radiation?
- A) Alpha particles
- B) Beta particles
- C) Gamma rays
- D) Neutrons
What does the term “radiation dose rate” refer to?
- A) Total dose received
- B) Dose delivered per unit time
- C) Maximum dose allowed
- D) Average dose over a lifetime
Which cellular response occurs at low doses of radiation?
- A) Immediate cell death
- B) Adaptive response
- C) Necrosis
- D) Cell transformation
What is the role of the p53 protein in response to radiation exposure?
- A) Promote cell division
- B) Regulate the cell cycle and induce apoptosis
- C) Enhance DNA replication
- D) Repair damaged tissues

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