EXAM #5 (Lectures 1 + 2) Flashcards
When an atom is ionized there is a change in it’s _____ properties.
When an atom is ionized there is a change in it’s chemical properties.
In a _____ bond the electrons between two atoms are shared to form the bond.
In a covalent bond the electrons between two atoms are shared to form the bond.
In an _____ bond, the atoms are bound together by the attraction
between oppositely-charged ions
In an ionic bond, the atoms are bound together by the attraction
between oppositely-charged ions
_____ are the basic functional unit of all plants and animals.
Cells are the basic functional unit of all plants and animals.
All living entities are made up of _____. _____ contains both _____ and
_____ compounds dissolved or suspended in water.
All living entities are made up of protoplasm. Protoplasm contains both organic and
inorganic compounds dissolved or suspended in water.
The 2 major parts of the cell are the _____ and the _____.
The 2 major parts of the cell are the nucleus and the cytoplasm.
Cells propagate through division. Germ cells are either a _____ or an _____. All other human cells are called _____ cells.
Cells propagate through division. Germ cells are either a sperm or an egg. All other human cells are called somatic cells.
Germ cells undergo two types of cell division, _____ and _____, followed by cellular differentiation into mature gametes, either _____ or _____.
Germ cells undergo two types of cell division, mitosis and meiosis, followed by cellular differentiation into mature gametes, either eggs or sperm.
Gametes are _____ cells.
They have only _____ set of chromosomes.
In humans, gametes have _____ chromosomes.
Gametes are haploid cells.
They have only one set of chromosomes.
In humans, gametes have 23 chromosomes.
For proliferation, a somatic cell undergoes _____. A somatic cell does not undergo _____.
For proliferation, a somatic cell undergoes mitosis. A somatic cell does not undergo meiosis.
Cells are most radio-sensitive in _____ and _____.
Cells are most radio-resistant in _____ phase.
Cells are most radio-sensitive in M and G2.
Cells are most radio-resistant in S phase.
Generally, mature, well-differentiated cells are _____ and immature,
undifferentiated, actively dividing cells are _____.
Generally, mature, well-differentiated cells are radioresistant and immature,
undifferentiated, actively dividing cells are radiosensitive.
The first step in producing a radiation response is _____
The first step in producing a radiation response is ionization
Electromagnetic: photons (x- and γ-rays) and neutrons are uncharged
particles and are _____ ionizing.
Electromagnetic: photons (x- and γ-rays) and neutrons are uncharged
particles and are indirectly ionizing.
The annual dose limit in US for Radiation Workers is
_____/year.
The annual dose limit in US for Radiation Workers is
50 mSv/year.
Physical units (absorbed dose) _____=100rad
Biologic units (equivalent dose) _____=100rem
Physical units (absorbed dose) Gray (Gy) 1Gy=100rad
Biologic units (equivalent dose) Sievert (Sv) 1Sv=100rem
_____ dose is used to assess the potential for biochemical changes in
specific tissues.
_____ dose is used to assess how much biological damage is expected from the absorbed dose.
Absorbed dose is used to assess the potential for biochemical changes in
specific tissues.
Equivalent dose is used to assess how much biological damage is expected from the absorbed dose.
Biological effects of ionizing radiation are determined by the
_____ _____ _____ not total energy of radiation
Biological effects of ionizing radiation are determined by the
individual packet size not total energy of radiation
~ two thirds of biological damage is caused by _____ action.
~ two thirds of biological damage is caused by indirect action.
_____: the dissociation of water molecules following irradiation.
Radiolysis: the dissociation of water molecules following irradiation.
_____ “fixes” (sets) the radical lesions in DNA in a form that cannot be easily
chemically repaired.
Therefore _____ is a very powerful radiosensitizer.
Oxygen “fixes” (sets) the radical lesions in DNA in a form that cannot be easily
chemically repaired.
Therefore oxygen is a very powerful radiosensitizer.
The oxygen effect is greater for _____ LET than _____ LET radiation
The oxygen effect is greater for low LET than high LET radiation
_____ is the average energy deposited per unit length of track (keV/um)
LET is the average energy deposited per unit length of track (keV/um)
_____ _____ is the depth of the soft tissue.
Track length is the depth of the soft tissue.
As the LET of radiation increases, the ability of the radiation to produce biological damage _____ ie. High LET radiation is _____ damaging to tissue than low LET radiation.
As the LET of radiation increases, the ability of the radiation to produce biological damage increases ie. High LET radiation is more damaging to tissue than low LET radiation.
X- and γ-rays are sparsely ionizing= _____ LET (~2/3 damage is indirect).
Neutrons and carbon ions are densely ionizing= _____ LET (most damage is direct).
X- and γ-rays are sparsely ionizing= low LET (~2/3 damage is indirect).
Neutrons and carbon ions are densely ionizing= high LET (most damage is direct).
Oxygen effect is greater for _____ LET (sparsely ionizing) radiation, and less for _____ LET (densely ionizing) radiation.
Oxygen effect is greater for low LET (sparsely ionizing) radiation, and less for high LET (densely ionizing) radiation.
OER is the _____ of RBE because OER depends on the _____ action of ionizing radiation.
OER is the inverse of RBE because OER depends on the indirect action of ionizing radiation.
RBE is maximal when the average distance between ionization events = distance between DNA strands = _____.
RBE is maximal when the average distance between ionization events = distance between DNA strands = 2nm.
To produce a given effect there must be one or more hits on a target (the target molecule of a cell is the _____ in the nucleus).
To produce a given effect there must be one or more hits on a target (the target molecule of a cell is the DNA in the nucleus).
Determine radiation effects by measuring _____ _____ not cell death.
Determine radiation effects by measuring cell survival not cell death.
Irradiation of cells with high-LET radiation produce linear survival curves.
Whereas, survival curves of cells exposed to low-LET radiation usually show some curvature.
Irradiation of cells with high-LET radiation produce linear survival curves.
Whereas, survival curves of cells exposed to low-LET radiation usually show some curvature.
