radiation effects on DNA chromosomes and cells

Question 1

what 3 levels may biological damage be observed on

Answer 1

molecular
cellular
organic

Question 2

any visible radiation injuries at the cellular or organic levels will ALWAYS begin where

Answer 2

with damage at the molecular level

Question 3

molecular damage results in…

Answer 3

the formation of structurally changed molecules, may impair cell functioning

Question 4

orange is what

Answer 4

phosphate group

Question 5

blue is what

Answer 5

carbon sugar molecule

Question 6

green/pink is what

Answer 6

nitrogen bases

Question 7

what are the four categories of radiation effects on DNA

Answer 7

base damage
single strand breaks
double strand breaks
crosslinks or crosslinking

Question 8

what is base damage

Answer 8

change or loss of a base, mutation

Question 9

what is a single strand reak

Answer 9

break in the backbone of one chain of a DNA molecule

Question 10

what is a double strand break

Answer 10

break in both chains of a DNA molecule

Question 11

what is crosslinks

Answer 11

within molecule (intrastrand)
one molecule to another (interstrand)

Question 12

is a single strand breaks repairable?

Answer 12

sometimes, with repair enzymes

Question 13

can double strand breaks be repaired?

Answer 13

,maybe, but harder than single
can be life threatening to cell

Question 14

double strand breaks occur more commonly with…

Answer 14

densely ionizing (high LET) radiaiton

Question 15

what happens when a double strand breaks is in the same rung of DNA

Answer 15

cleaved or broken chromosome, if it divides the cell will die, or have impaired functioning

Question 16

covalent cross-links happen by:

Answer 16

directly by high LET
indirectly by low LET

Question 17

what chromosome anomalies CNA results from radiation

Answer 17

chromosome aberrations
chromatid aberrations

Question 18

when does chromosome aberration damage occur

Answer 18

before S-phase (duplication)

Question 19

when does chromatid aberrations damage occur

Answer 19

after S-phase
only one daughter cell affected

Question 20

during what stage are cells the absolute most radiosensitive

Answer 20

cells in mitosis

Question 21

what is the restitution rate of structural changes to the cells

Answer 21

95% meaning/healing

Question 22

what happens when deletion occurs

Answer 22

fragments are lost during mitosis
only part of chromosome gets replicated, creates an acentric fragment (no centromere)

Question 23

what can result from two breaks in a single chromatid

Answer 23

ring chromatid
acentric fragment

Question 24

what broken-end rearrangements (non visible) can occur

Answer 24

translocations and inversions

Question 25

what is instant death

Answer 25

high doses DNA just breaks up

Question 26

what is reproductive death

Answer 26

cell survives but cannot replicate

Question 27

what is apoptosis

Answer 27

programmed cell death

Question 28

apoptosis occurs in what stage

Answer 28

interphase

Question 29

what is miotic it genetic death

Answer 29

cell dies while trying to dvide

Question 30

what is mitotic delay

Answer 30

delay in division

Question 31

what are the applications of dose response relationships

Answer 31

therapeutic radiation-protection

Question 32

what effect is produced if the radiation response increases in severity

Answer 32

deterministic effect

Question 33

what effect is produced if the radiation response increases in incidence

Answer 33

stochastic effect

Question 34

what does the stochastic effect mean

Answer 34

that chances of occurrence increase with additional exposure

Question 35

what are the two characteristics of every radiation dose relationship

Answer 35

1. linear or non linear 2. threshold or non threshold

Question 36

what are the characteristics of the dose response relationships for diagnostic radiology

Answer 36

linear nin-threshold **small doses has ow risks

Question 37

A indicates what

Answer 37

a large response from a very small dose

Question 38

b indicates what

Answer 38

low doses low response, high doses produce much higher response

Question 39

c indicates what

Answer 39

no response below threshold, increase in response until the inflection point