EXAM #5 (Lectures 1 + 2)

Question 1

When an atom is ionized there is a change in it’s _____ properties.

Answer 1

When an atom is ionized there is a change in it’s chemical properties.

Question 2

In a _____ bond the electrons between two atoms are shared to form the bond.

Answer 2

In a covalent bond the electrons between two atoms are shared to form the bond.

Question 3

In an _____ bond, the atoms are bound together by the attraction
between oppositely-charged ions

Answer 3

In an ionic bond, the atoms are bound together by the attraction
between oppositely-charged ions

Question 4

_____ are the basic functional unit of all plants and animals.

Answer 4

Cells are the basic functional unit of all plants and animals.

Question 5

All living entities are made up of _____. _____ contains both _____ and
_____ compounds dissolved or suspended in water.

Answer 5

All living entities are made up of protoplasm. Protoplasm contains both organic and
inorganic compounds dissolved or suspended in water.

Question 6

The 2 major parts of the cell are the _____ and the _____.

Answer 6

The 2 major parts of the cell are the nucleus and the cytoplasm.

Question 7

Cells propagate through division. Germ cells are either a _____ or an _____. All other human cells are called _____ cells.

Answer 7

Cells propagate through division. Germ cells are either a sperm or an egg. All other human cells are called somatic cells.

Question 8

Germ cells undergo two types of cell division, _____ and _____, followed by cellular differentiation into mature gametes, either _____ or _____.

Answer 8

Germ cells undergo two types of cell division, mitosis and meiosis, followed by cellular differentiation into mature gametes, either eggs or sperm.

Question 9

Gametes are _____ cells.
They have only _____ set of chromosomes.
In humans, gametes have _____ chromosomes.

Answer 9

Gametes are haploid cells.
They have only one set of chromosomes.
In humans, gametes have 23 chromosomes.

Question 10

For proliferation, a somatic cell undergoes _____. A somatic cell does not undergo _____.

Answer 10

For proliferation, a somatic cell undergoes mitosis. A somatic cell does not undergo meiosis.

Question 11

Cells are most radio-sensitive in _____ and _____.

Cells are most radio-resistant in _____ phase.

Answer 11

Cells are most radio-sensitive in M and G2.

Cells are most radio-resistant in S phase.

Question 12

Generally, mature, well-differentiated cells are _____ and immature,
undifferentiated, actively dividing cells are _____.

Answer 12

Generally, mature, well-differentiated cells are radioresistant and immature,
undifferentiated, actively dividing cells are radiosensitive.

Question 13

The first step in producing a radiation response is _____

Answer 13

The first step in producing a radiation response is ionization

Question 14

Electromagnetic: photons (x- and γ-rays) and neutrons are uncharged
particles and are _____ ionizing.

Answer 14

Electromagnetic: photons (x- and γ-rays) and neutrons are uncharged
particles and are indirectly ionizing.

Question 15

The annual dose limit in US for Radiation Workers is

_____/year.

Answer 15

The annual dose limit in US for Radiation Workers is

50 mSv/year.

Question 16

Physical units (absorbed dose) _____=100rad

Biologic units (equivalent dose) _____=100rem

Answer 16

Physical units (absorbed dose) Gray (Gy) 1Gy=100rad

Biologic units (equivalent dose) Sievert (Sv) 1Sv=100rem

Question 17

_____ 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.

Answer 17

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.

Question 18

Biological effects of ionizing radiation are determined by the
_____ _____ _____ not total energy of radiation

Answer 18

Biological effects of ionizing radiation are determined by the
individual packet size not total energy of radiation

Question 19

~ two thirds of biological damage is caused by _____ action.

Answer 19

~ two thirds of biological damage is caused by indirect action.

Question 20

_____: the dissociation of water molecules following irradiation.

Answer 20

Radiolysis: the dissociation of water molecules following irradiation.

Question 21

_____ “fixes” (sets) the radical lesions in DNA in a form that cannot be easily
chemically repaired.

Therefore _____ is a very powerful radiosensitizer.

Answer 21

Oxygen “fixes” (sets) the radical lesions in DNA in a form that cannot be easily
chemically repaired.

Therefore oxygen is a very powerful radiosensitizer.

Question 22

The oxygen effect is greater for _____ LET than _____ LET radiation

Answer 22

The oxygen effect is greater for low LET than high LET radiation

Question 23

_____ is the average energy deposited per unit length of track (keV/um)

Answer 23

LET is the average energy deposited per unit length of track (keV/um)

Question 24

_____ _____ is the depth of the soft tissue.

Answer 24

Track length is the depth of the soft tissue.

Question 25

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.

Answer 25

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.

Question 26

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).

Answer 26

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).

Question 27

Oxygen effect is greater for _____ LET (sparsely ionizing) radiation, and less for _____ LET (densely ionizing) radiation.

Answer 27

Oxygen effect is greater for low LET (sparsely ionizing) radiation, and less for high LET (densely ionizing) radiation.

Question 28

OER is the _____ of RBE because OER depends on the _____ action of ionizing radiation.

Answer 28

OER is the inverse of RBE because OER depends on the indirect action of ionizing radiation.

Question 29

RBE is maximal when the average distance between ionization events = distance between DNA strands = _____.

Answer 29

RBE is maximal when the average distance between ionization events = distance between DNA strands = 2nm.

Question 30

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).

Answer 30

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).

Question 31

Determine radiation effects by measuring _____ _____ not cell death.

Answer 31

Determine radiation effects by measuring cell survival not cell death.

Question 32

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.

Answer 32

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.