Chapter 8: Cell Survival Curves & Mechanisms of Cell Killing

Question 1

A ________ measures the number of living cells. It is _______ and takes _________.

Answer 1

viability assay
quick
24-72 hours

Question 2

A __________ measures the number of clones produced by seeded cells. It is ________ and takes _________. It is __________.

Answer 2

clonogenic assay
more difficult to measure
1-2 weeks
more relevant to clinical treatment outcome

Question 3

A cell survival curve describes the relationship between ___________ and ___________.

Answer 3

radiation dose
proportion of cells that survive

Question 4

For differentiated cells that do not proliferate, death is ___________.

Answer 4

loss of a specific function

Question 5

For proliferating cells, death is __________.

Answer 5

loss of reproductive integrity.

Question 6

In radiobiology a cell is dead if it has lost the capacity to _________ and produce _____________.

Answer 6

divide indefinitely
large number of progeny

Question 7

A __________ retains its reproductive integrity and is able to proliferate indefinitely to produce a colony.

Answer 7

clonogenic cell

Question 8

For tumors, cells are dead if they are ________ and cause __________.

Answer 8

unable to divide
further growth/spread of malignancy

Question 9

__________ is the dominant mechanism following irradiation for most cells.

Answer 9

Mitotic death

Question 10

A dose of _______ is needed to destroy cell function in non-proliferating systems. The mean lethal dose for loss of proliferative capacity is __________.

Answer 10

100 Gy
2 Gy

Question 11

To produce a cell survival curve, a ________ is necessary.

Answer 11

clonogenic assay

Question 12

Plating efficiency is the percentage of cells seeded that _________. The formula is _________. This is typically calculated on the _________ plate.

Answer 12

grow into colonies
[number of colonies counted/number of cells seeded]x100%
control

Question 13

Dead cells that have not divided and show evidence of nuclear deterioration go through ____________.

Answer 13

apoptotic death

Question 14

The surviving fraction is given by: ________.

Answer 14

= Colonies counted / [Cells seeded x (PE/100)]

Question 15

For survival curves of mammalian cells dose is plotted on ________ and surviving fraction on _________.

Answer 15

linear scale
logarithmic scale

Question 16

The _________ model of cell survival is based on the concept that a number of critical targets have to be inactivated for cells to be killed.

Answer 16

target theory

Question 17

A single-hit, single-target survival curve is a ___________ line on a ___________ plot. This curve applies to inactivation of _______ and _______, and to ___________, __________, _________.

Answer 17

straight
semilogarithmic plot
viruses
bacteria
radiosensitive mammalian cells
response to very low dose rates
response to high LET radiation

Question 18

When a dose gives an average of 1 hit/target, the survival fraction is ___________.

Answer 18

0.37

Question 19

_________ is programmed cell death

Answer 19

apoptosis

Question 20

__________ is from acute cellular injury and culminates in the release of intracellular components.

Answer 20

necrosis

Question 21

________ is when cells undergo rapid proliferation causing telomeres of their chromosomes to become a lot shorter. eventually cell growth decelerates and cells enter permanent cell-cycle arrest.

Answer 21

senescence

Question 22

________ is mechanism where long-lived proteins and organelles are directed to and degraded within lysosomes.

Answer 22

Autophagy

Question 23

_________ is caused by not producing proper chromosome segregation and cell division, but results in cell death or formation of nonviable cells.

Answer 23

mitotic cell death

Question 24

Belgian scientist Christian de Duve won Nobel prize for discovery of __________.

Answer 24

lysosome

Question 25

The lysosome _________ cellular contents which provides the cell with ________ and ________ for renewal.

Answer 25

digests
nutrients
building blocks

Question 26

________ has major role in innate immune defense by effectively killing pathogens. Also an initiating branch of ________ immune response.

Answer 26

Phagocytosis
adaptive

Question 27

Mitotic cell death is frequently followed by __________.

Answer 27

apoptosis

Question 28

For gels with cells undergoing apoptosis it creates a _________ but for cells undergoing necrosis it creates a _________.

Answer 28

smear

Question 29

Exchange type aberrations require ______ chromosome breaks.

Answer 29

2

Question 30

At low doses the two breaks may result from ___________. Causes survival curve to be ________.

Answer 30

passage of single electron
linear

Question 31

At high doses the two breaks may result from __________. Causes survival curve to be __________. Probability of interaction between the two breaks is proportional to __________.

Answer 31

two separate electrons
quadratic
square of dose

Question 32

Mitotic death principally results from _____________. The associated cell survival curve is ______________.

Answer 32

exchange-type chromosome aberrations
curved in log-linear plot

Question 33

Apoptotic death results from _________. The associated cell survival curve is _________.

Answer 33

unknown mechanisms
straight line on log-linear plot

Question 34

The _________ is the induction of biologic effects in cells that are not directly traversed by a charged particle but are in proximity to cells that are. Typically done using ___________.

Answer 34

bystander effect
alpha particles