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WorksheetsRadiation Biology and Effects Quiz
Total questions: 46
Worksheet time: 23mins
What is the basic functional unit of all plants and animals?
Atom
Molecule
Cell
Tissue
What percentage of the human body is composed of water?
50%
60%
70%
~80%
What is the most radiosensitive target molecule in a human cell?
RNA
Proteins
DNA
Lipids
Meiosis affects which type of cells?
Somatic cells
Genetic cells
Epithelial cells
Muscle cells
When a cell is NOT undergoing mitosis or meiosis, it is in:
Prophase
Interphase
Metaphase
Cytokinesis
In which phase is chromosome damage from radiation typically observed?
Interphase
Prophase
Metaphase
Telophase
The probability of a radiation “hit” increases with:
Low oxygen and low LET
High oxygen and high LET
Low oxygen and high LET
High oxygen and low LET
In which phase of the cell cycle are human cells MOST radiosensitive?
G1 phase
S phase
G2 phase
M phase
Which type of radioactive particle has the highest LET?
Beta particles
Gamma rays
X-rays
Alpha particles
Compared to low-LET radiation, the mean lethal dose for high-LET radiation is:
Higher
Lower or the same
The same for all types of radiation
Unrelated to LET
Oxygen presence during low-LET radiation results in:
No change in radiation effect
Decreased radiation effect
Maximal radiation effect
Reduced cell death
What happens when oxygen is present during high-LET radiation exposure?
Radiation effect increases
Radiation effect remains the same
Radiation effect decreases
Oxygen has no influence
What are the two types of irradiation hits?
Internal and external
Direct and indirect
High-dose and low-dose
Acute and chronic
What happens in a main-chain scission?
A macromolecule is broken into smaller molecules
A DNA strand is repaired
A free radical is formed
A chromosome undergoes duplication
What type of DNA damage may not be reversible?
Single-strand break
Base change/loss
Chromosome aberration
Cross-linking
What can radiation damage to DNA cause?
Mutations
Cell death
Carcinogenesis
All of the above
The principal radiation interaction in the human body occurs with:
Proteins
Lipids
Water (H2O)
DNA
What is radiolysis?
The splitting of a DNA strand by radiation
The breakdown of cellular proteins by radiation
The radiation-induced breakdown of water molecules
The repair process of radiation-damaged cells
What does an irradiated water molecule first dissociate into?
Hydrogen peroxide
An ion pair (H+ and OH⁻)
DNA fragments
Carbon dioxide
Two OH* free radicals can combine to form:
Hydrogen peroxide (H2O2)
Oxygen gas
Carbon dioxide
Water vapor
Why can free radicals be damaging?
They stabilize molecular structures
They are highly reactive and can damage DNA
They decrease cell metabolism
They promote cell growth
The molecule most affected by an indirect effect of ionizing radiation is:
DNA
RNA
Water
Protein
What is the definition of LET (Linear Energy Transfer)?
The rate at which radiation loses energy as it passes through tissue
The total radiation dose absorbed by an organ
The amount of radiation exposure in the air
The number of free radicals produced by radiation
As LET increases, what happens to RBE (Relative Biological Effectiveness)?
RBE decreases
RBE remains unchanged
RBE increases
LET and RBE are unrelated
What is the LET of diagnostic X-rays?
1.0 keV/μm
3.0 keV/μm
5.0 keV/μm
10.0 keV/μm
What is the RBE of diagnostic X-rays?
0.5
1.0
2.0
5.0
The presence of high oxygen levels has what effect on tissue radiosensitivity?
Increases radiosensitivity
Decreases radiosensitivity
Has no effect
Only affects high-LET radiation
Why are radioprotective agents not used in humans?
They are too expensive
They cause excessive radiation absorption
They are fatally toxic
They are ineffective
When can human cells NOT recover from radiation damage?
After apoptosis
After mitosis
After interphase death
After metaphase
What is hormesis?
The theory that low doses of radiation may be beneficial
A process where cells repair themselves after high radiation exposure
The development of cancer due to radiation exposure
The immediate cell death caused by radiation
Which of the following is considered a low-LET radiation?
Alpha particles
X-rays
Neutrons
Heavy ions
A loss or change in a DNA base sequence is called a:
Frame shift
Deletion
Mutation
Translocation
Direct action of radiation damage is more likely with:
Low-LET radiation
High-LET radiation
Radiation with low RBE
Shielded cells
The rungs of the DNA ladder-like structure are made of:
Pairs of nitrogenous bases
Sugar molecules
Phosphate groups
Hydrogen bonds
Which of the following are classified as purines in DNA?
Cytosine and Thymine
Adenine and Guanine
Uracil and Guanine
Adenine and Cytosine
Which cell structure contains centrioles?
Nucleus
Mitochondria
Centrosome
Ribosome
Who was the first American radiation worker to die from radiation-induced cancer in 1904?
Wilhelm Roentgen
Marie Curie
Clarence Dally
Henri Becquerel
What does 0.2 Gy equal?
20 mGy
200 mGy
2 mGy
2000 mGy
What is the definition of air kerma?
Absorbed dose per unit volume
Kinetic energy released in air per unit mass
The dose received by a patient during radiation therapy
The ionization produced in tissue by radiation
What is Dose Area Product (DAP)?
The product of dose and exposure time
The product of absorbed dose and area irradiated
A unit of radiation energy
The energy of an X-ray photon
Radiation weighting factors take into consideration:
The mass of the irradiated object
The type and energy of radiation
The temperature of the irradiated area
The speed of radiation travel
1 Gy is equivalent to:
1 J/kg
100 rad
1000 rem
Both a and b
Which types of ionizing radiation produce virtually the same biological effect in tissue for equal absorbed doses?
X-rays, gamma rays, beta particles
Alpha particles, neutrons, protons
Beta particles, positrons, heavy ions
Neutrons, gamma rays, alpha particles
What is the definition of exposure?
The amount of ionization produced in air by X-rays or gamma rays
The absorbed dose in a patient’s tissue
The biological effect of radiation
The shielding effect of protective barriers
What is the formula for effective dose?
Absorbed dose × Radiation weighting factor × Tissue weighting factor
Absorbed dose ÷ Exposure time
LET × RBE
Air kerma × Distance²
What is the radiation weighting factor for alpha particles?
1
5
10
20
