Radiation Biology — MCQs Biology

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1. Radiation biology studies:
(A) Effects of ionizing and non-ionizing radiation on living organisms
(B) Plant photosynthesis
(C) Animal reproduction only
(D) Human digestion

2. Ionizing radiation includes:
(A) Visible light only
(B) X-rays, gamma rays, alpha particles, beta particles
(C) Microwaves only
(D) Infrared radiation only

3. Non-ionizing radiation includes:
(A) Ultraviolet (UV), visible light, microwaves, radio waves
(B) X-rays and gamma rays
(C) Alpha and beta particles
(D) Cosmic rays only

4. The unit of absorbed radiation dose is:
(A) Gray (Gy)
(B) Sievert (Sv)
(C) Rem
(D) Curie

5. The unit measuring biological effect of radiation is:
(A) Gray (Gy)
(B) Sievert (Sv)
(C) Curie
(D) Becquerel

6. Acute radiation syndrome occurs due to:
(A) Low-dose chronic exposure
(B) High-dose exposure in a short time
(C) UV exposure only
(D) Cell mutation only

7. Chronic radiation exposure can lead to:
(A) Cancer, cataracts, genetic mutations
(B) Immediate death only
(C) Fever and headache only
(D) Hair growth only

8. DNA is highly sensitive to:
(A) Ultrasound
(B) Microwaves only
(C) Visible light only
(D) Ionizing radiation

9. Radiation can damage cells by:
(A) Only water evaporation
(B) Only protein degradation
(C) Only lipid formation
(D) Direct DNA breakage or indirect free radical formation

10. Free radicals generated by radiation primarily affect:
(A) Blood only
(B) DNA, proteins, and cell membranes
(C) Bones only
(D) Muscles only

11. Linear energy transfer (LET) refers to:
(A) Energy deposited per unit length of tissue by radiation
(B) Blood flow in vessels
(C) Rate of oxygen transport
(D) Rate of photosynthesis

12. High LET radiation includes:
(A) Microwaves
(B) X-rays and gamma rays
(C) UV light
(D) Alpha particles, neutrons

13. Low LET radiation includes:
(A) Alpha particles only
(B) X-rays, gamma rays, beta particles
(C) Neutrons only
(D) UV only

14. The most radiosensitive human cells are:
(A) Skin cells only
(B) Muscle cells only
(C) Neurons only
(D) Lymphocytes, bone marrow stem cells, intestinal crypt cells

15. The least radiosensitive human cells are:
(A) Lymphocytes
(B) Bone marrow cells
(C) Intestinal cells
(D) Neurons and muscle cells

16. Deterministic effects of radiation:
(A) Have a threshold dose; severity increases with dose
(B) Occur randomly with no threshold
(C) Only genetic mutations
(D) Only cancer development

17. Stochastic effects of radiation:
(A) Occur by chance; probability increases with dose, severity is independent of dose
(B) Only immediate death
(C) Only burns
(D) Only cataracts

18. Acute radiation syndrome manifests in:
(A) Hematopoietic, gastrointestinal, and neurovascular phases
(B) Only skin burns
(C) Only fever
(D) Only muscle pain

19. Hematopoietic syndrome is due to:
(A) Muscle injury only
(B) Damage to liver only
(C) Damage to bone marrow stem cells
(D) Kidney failure only

20. Gastrointestinal syndrome results from:
(A) Brain tissue only
(B) Blood only
(C) Damage to intestinal lining
(D) Skin only

21. Neurovascular syndrome is caused by:
(A) Damage to central nervous system and blood vessels at very high doses
(B) Blood sugar only
(C) Heart failure only
(D) Lung infection only

22. Radiation-induced mutations can be:
(A) Somatic or germline
(B) Only beneficial
(C) Only lethal
(D) Only in plants

23. Somatic mutations affect:
(A) Offspring only
(B) The individual exposed
(C) Entire population
(D) Only plants

24. Germline mutations affect:
(A) Only organs
(B) Only the exposed individual
(C) Only tissues
(D) Future generations

25. Radiation-induced cancer is usually:
(A) A stochastic effect
(B) A deterministic effect
(C) Immediate
(D) Only visible in skin

26. Radiotherapy uses:
(A) Targeted ionizing radiation to destroy cancer cells
(B) UV radiation to treat bones
(C) Microwaves for digestion
(D) X-rays for vitamins

27. Fractionated radiotherapy is used to:
(A) Increase radiation dose at once
(B) Minimize damage to normal tissues while treating tumors
(C) Treat only infections
(D) Enhance vitamin production

28. Radiosensitizers:
(A) Make cancer cells more sensitive to radiation
(B) Protect normal cells only
(C) Treat infections only
(D) Heal burns

29. Radioprotectors:
(A) Protect normal cells from radiation damage
(B) Enhance tumor growth
(C) Amplify DNA only
(D) Destroy cancer cells only

30. Linear-quadratic model predicts:
(A) Cell metabolism only
(B) DNA mutation rate only
(C) Cancer incidence only
(D) Cell survival after different doses of radiation

31. Relative biological effectiveness (RBE) compares:
(A) DNA replication speed
(B) Blood type differences
(C) Biological effectiveness of different radiations for the same dose
(D) Enzyme activity

32. Radiation hormesis suggests:
(A) Only UV is beneficial
(B) All radiation is harmful
(C) Low doses of radiation may have beneficial effects
(D) Only X-rays are beneficial

33. Background radiation comes from:
(A) Only UV light
(B) Only medical X-rays
(C) Cosmic rays, soil, rocks, natural radionuclides
(D) Only microwaves

34. Radiobiology studies help in:
(A) Only plant growth
(B) Radiation therapy, safety, and environmental protection
(C) Only animal reproduction
(D) Photosynthesis studies only

35. ALARA principle in radiation protection means:
(A) As Long As Radiation Acts
(B) Always Leave All Radiation Alone
(C) Average Level And Radiation Assessment
(D) As Low As Reasonably Achievable

36. Radiation shielding involves using:
(A) Paper only
(B) Wood only
(C) Lead, concrete, or water to absorb radiation
(D) Plastic only

37. Acute effects of radiation can include:
(A) DNA repair only
(B) Genetic mutation only
(C) Cancer only
(D) Skin erythema, nausea, vomiting, hair loss

38. Chronic effects of radiation include:
(A) Cancer, cataracts, infertility
(B) Fever only
(C) Muscle pain only
(D) Heart attack only

39. The LD50/60 dose represents:
(A) Dose for 100% survival
(B) Radiation dose lethal to 50% of exposed population within 60 days
(C) Dose causing mutations only
(D) Dose for vitamin production

40. Radiation-induced cataracts result from:
(A) Bone marrow damage
(B) Lens epithelial cell damage
(C) Skin damage
(D) Blood cell damage

41. Cytogenetic dosimetry uses:
(A) DNA profiling only
(B) Chromosomal aberrations to estimate radiation dose
(C) Hair analysis only
(D) Bone density only

42. Double-strand DNA breaks are:
(A) Only in plants
(B) Only beneficial
(C) Lethal or mutagenic lesions caused by ionizing radiation
(D) Only reversible

43. Radiosensitivity is highest in cells that are:
(A) Mature neurons
(B) Non-dividing
(C) Rapidly dividing
(D) Muscle cells

44. Radioprotective agents include:
(A) Antibiotics only
(B) Amifostine, antioxidants, cysteine derivatives
(C) Vitamins only
(D) Hormones only

45. Whole-body exposure to high-dose radiation may cause:
(A) Only hair loss
(B) Multi-organ failure and death
(C) Only skin burn
(D) Only nausea

46. Radiation can indirectly damage DNA by:
(A) Absorbing light only
(B) Producing reactive oxygen species (ROS)
(C) Producing heat only
(D) Increasing enzyme activity only

47. Radiation-induced apoptosis occurs via:
(A) Activation of DNA damage response and cell death pathways
(B) Protein synthesis only
(C) Muscle contraction only
(D) Cell division only

48. Shielding, time limitation, and distance are methods to:
(A) Measure radiation only
(B) Increase radiation exposure
(C) Amplify radiation
(D) Reduce radiation exposure

49. Linear energy transfer (LET) is higher for:
(A) Microwaves than UV
(B) Gamma rays than alpha particles
(C) Alpha particles than gamma rays
(D) UV than X-rays

50. Radiation-induced DNA repair mechanisms include:
(A) Only replication
(B) Only transcription
(C) Only translation
(D) Base excision repair, nucleotide excision repair, double-strand break repair