Rad Bio: Unit 3 Exam

0.0(0)
studied byStudied by 0 people
learnLearn
examPractice Test
spaced repetitionSpaced Repetition
heart puzzleMatch
flashcardsFlashcards
Card Sorting

1/74

Study Analytics
Name
Mastery
Learn
Test
Matching
Spaced

No study sessions yet.

75 Terms

1
New cards
term image

Linear non-threshold

2
New cards
term image

Linear threshold

3
New cards
<p> </p>

Non-linear non-threshold

4
New cards
term image

Non-linear, threshold

5
New cards

Linear response

Straight line - steady increase; response is directly proportional to the dose (ex. dose is doubled, response to radiation is doubled)

6
New cards

Threshold response

Intercepts dose axis at some value greather than 0; at lower doses (to the left of the line intersecting the dose axis) no response expected

7
New cards

Non-threshold response

Intersects dose axis at 0; any dose, regardless of size, carries some risk

Damage to one or just a few cells can produce a response

8
New cards

Non-linear response

Not a straight line; response is not directly proportional to the dose

9
New cards

Linear, non-threshold dose response relationship

Radiation induced cancer

10
New cards

Non-linear, threshold dose response relationship

Early effects of radiation and cataracts

11
New cards

Radiation Hormesis

Low doses of radiation are beneficial stimulating the activation of repair mechanisms that protect against disease

12
New cards

Radiation dose - response

A mathematical relationship between various radiation dose levels and the magnitude of the observed response

13
New cards
<p>A</p>

A

Linear non-threshold

14
New cards
<p>B</p>

B

Non-linear non-threshold

15
New cards
<p>C</p>

C

Linear threshold

16
New cards
<p>D</p>

D

Non-linear threshold

17
New cards

Which dose response relationship tells us why its important to follow ALARA?

Linear non-treshold

18
New cards

In vivo

Inside the cell or body; increased radiosensitivity

19
New cards

In vitro

Outside the cell or body

20
New cards

What three main effects are possible of irradiation of macromolecules?

Main chain scission, cross linking and point lesions

21
New cards

Main Chain Scission

The breakage of the backbone of a long chain molecule, reduces viscosity of a solution in the cell (single or double strand break)

22
New cards

Cross Linking

Side of structure becomes “sticky” and will attach to neighboring macromolecules or other parts of the same molecule; increases viscosity of a macromolecular solution

23
New cards

What is another name for point lesions?

Base pair lesion

24
New cards

Point lesions

Disruption of a single chemical bond in a macromolecule causing a break (it is possible an incorrect molecule can be replaced)

25
New cards

What type of radiation most commonly causes point lesions?

Low let radiation

26
New cards

What type of radiation is more likely with direct effect?

High let radiation

27
New cards

DNA structure

Double stranded helix (twisted ladder) with side rails of ladder composed of sugar molecules bound together by a phosphate

28
New cards

What does adenine pair to?

Thymine

29
New cards

What does guanine pair to?

Cytosine

30
New cards

Mutations

Unrepaired damage of incorrect genetic material that can be transferred to a daughter cell that can occur in somatic and genetic cells

31
New cards

Single strand break

One bond is severed; one side of ladder, easier to repair, common with low let radiation

32
New cards

Double strand break

Both sides break, harder to repair, common with high let radiation

33
New cards
<p>A? </p>

A?

Single strand break

34
New cards
<p>B? </p>

B?

Double strand break

35
New cards

With what radiation does single strand breaks occur more with?

Low let radiation

36
New cards

With what radiation does double strand breaks occur more with?

High let radiation

37
New cards
<p>C?</p>

C?

Cross linking

38
New cards
<p>D? </p>

D?

Point lesion

39
New cards

Karotype

Chromosome map

40
New cards

What happens to chromosomal fragments?

  • Rejoin to configuration

  • Fail to rejoin and create an aberration

  • Join with another broken fragment creating a new chromosome

41
New cards

If there is irradiation in early interphase (pre s phase), if it is not repaired before the s phase what happens to the break?

It is replicated

42
New cards

If there is irradiation in late interphase (post s phase), what happens to the break?

It is only affected to one daughter cell

43
New cards

What phase of cell division is best to visualize radiation induced chromosome breaks microscopically?

Metaphase

44
New cards

Radiation induced malignant disease is caused by…?

Rapid proliferation of abnormal cells

45
New cards

Direct Effect

Irradiation to target molecule (DNA)

46
New cards

Indirect Effect

Irradiation to water (can later effect DNA)

47
New cards

The principal effect on radiation to humans is…?

Indirect effect

48
New cards

When water (H2O) is irradiation it loses an electron (e-), what is the molecule and charge after irradiation?

HOH+

49
New cards

After irradiation, the ejected electron (e-) tries to bond with another water molecule to form water again, what molecule and charge is now created?

HOH-

50
New cards

HOH+ breaks down into what?

H+

OH*

51
New cards

HOH- breaks down into what?

OH-

H*

52
New cards

What is H* and OH*?

Free radicals

53
New cards

Free radicals can create what two things?

Point lesions and toxins

54
New cards

What toxin is created from OH*?

H2O2

55
New cards

H2O2

Hydrogen peroxide

56
New cards

What toxin is created from H*?

HO2

57
New cards

HO2

Hydroperoxyl

58
New cards

Free Radicals

Uncharged, unstable molecules with excess energy that can be transferred to other molecules/DNA and distrupt bonds & produce point lesions

59
New cards

H* + O2 =

HO2

60
New cards

OH* + OH =

H2O2

61
New cards

What happens when radiation interacts with a target?

A hit occurs

62
New cards

Low LET and absence of oxygen = ______ hits

Low

63
New cards

Low LET and presence of oxygen = ______ hits

High

64
New cards

High LET and absence of oxygen = ______ hits

High

65
New cards

High LET and presence of oxygen = ______ hits

No additional

66
New cards

Double strand DNA breaks are more likely to occur after a dose of…?

High let radiation

67
New cards

Free radicals are an example of…?

Indirect effect

68
New cards

Single-target, single-hit

Simple cells, less radiation needed to cause cell death; non-threshold

69
New cards

Multi-target, single-hit

Human cells, more radiation needed to cause cell death; threshold

70
New cards

Low D37 = __________ radiosensitivity

High

71
New cards

High D37 = __________ radiosensitivity

Low

72
New cards

D37

Dose to kill 63% of cells

37% survival

73
New cards

DO

Mean lethal dose

74
New cards

Which has a greater mean lethal dose: low or high let radiation?

Low

75
New cards

Dq

Threshold dose