Ch2 Irradiation damage

Question 1

Raditation damage to cells charcteristics (4)

Answer 1

• Interaction of radiation in cells is a chance
• Visible changes in the cell are not unique
• Energy is deposited quickly and randomly in the cell
• Biological changes occure only after a period of time (latent period)

Question 2

What is the target of basic interactions

Answer 2

DNA

Question 3

What are the basic interaction (2)

Answer 3

• Direct hit
• Indirect hit

Question 4

What is direct hit interaction

Answer 4

When DNA is ionized

Question 5

What is indirect hit interaction

Answer 5

Involves bonding with ions and free radicals

Question 6

DNA strand is made up of (3)

Answer 6

• Nitrogenous base
• Sugar
• Phosphoric acid

Question 7

What are the DNA damage types (4)

Answer 7

• base damage
• Single strand break
• Double strand break
• Crosslinks

Question 8

Changes in DNA are reflected in ___

Answer 8

Chromosomes

Question 9

Chromatid aberrations are produced when cells are irradiated ___ ___ ___

Answer 9

After DNA synthesis

Question 10

Chromosome aberrations are produced when cells are irradiated ___ ___ ___

Answer 10

Before DNA synthesis

Question 11

Describe single strand break

Answer 11

Break in one strand of DNA molecule. A supporting structure (base) is stripped away

Question 12

Describe double strand break

Answer 12

• Breaks in both backbones of DNA
• Strand snaps in 2 pices
• Most important lesion produced by radiation***

Question 13

Double strand break results (3)
- Treated as single strand break if
- May result in ___ or ___
- Significant for ___ ___

Answer 13

• Breaks are non adjacent or in proximity
• Mutation, carcinogenesis
• Cell kill

Question 14

Base damage description

Answer 14

The loss or change of a base (A,G,T,C) on the DNA strand

Question 15

Base damage result (2)

Answer 15

• Changes sequence of bases — Changes genetic info — mutation
• Cell death

Question 16

Crosslinking DNA
- description
- Results

Answer 16

• Bonds formed between 2 regions of the same strand, from one DNA to another and one DNA to a protein
• Unclear significance to cell kill

Question 17

What are the three changes to chromosomes

Answer 17

• Restitution
• Aberration
• Rearrangement

Question 18

What is chromosome restitution

Answer 18

Broken ends rejoin with no visible damage

Question 19

Chromosome aberration is when

Answer 19

part of the chromosome is lost at the next mitosis

Question 20

What is chromosome rearrangment

Answer 20

when Broken ends cause mutations and loss of genetic material

Question 21

A change in chromosomes means a change in ___ reslulting in changes in ___ ___

Answer 21

• DNA
• Genetic material

Question 22

What are acentric and dicentric chromotid rings
- ___ is broken into ___ fragments
- 2 with ___ and 2 ___

Answer 22

• Chromosme, 4
• centromeres, without

Question 23

Ring chromosomes
- One break…
- Two ends…

Answer 23

• in each arm of same chromosome
• join together forming a ring

Question 24

chromosome stickiness
- chromosomes clump together during ___
- Cant ___ and go to seperate ___

Answer 24

• Metaphase
• Seperate, spindles

Question 25

Effects on somatic cells may have a

Answer 25

clnical impact

Question 26

Effects on germ cells producing genetic mutations may be carried over

Answer 26

to new generation

Question 27

Dicentric fragments have ___ centromeres

Answer 27

2

Question 28

Ancentric have ___ centromeres

Answer 28

No

Question 29

Ring chromosomes - Ring is replicated and ... - Replicated rings are ___ and ___ becomes impossible resulting in ___ ___

Answer 29

- transmitted to a daughter cell - Intertwined, anaphase, cell death

Question 30

Loss of a part (deletion) results in ___ fragmenation

Answer 30

Acentric fragmentation

Question 31

Rearangement of broken chromosome ends result in (4)

Answer 31

- Ring - Dicentric - Anaphase bridge - chromosomes

Question 32

Rearangement of broken ends WITH NO VISIBLE DAMAGE result in (2)

Answer 32

- Genertic mutations - Inheritable characteristics

Question 33

Translocations are formed by

Answer 33

A break in the arms of 2 different chromosomes

Question 34

Symmetrical Translocation - Lethal? - Associated with - Activates a

Answer 34

- No - Several malignancies - Oncogene

Question 35

Deletion formed by

Answer 35

2 breaks in the same arm of a chromosome, a fragment is deleted creating a short and long arm

Question 36

Deletion - lethal? - Associated with

Answer 36

- No - Carciogenesis of lost genetic material including a supressor gene

Question 37

Inversion

Answer 37

2 breaks in the same arm of a chromosome, a fragment is fliped flopped on the same arm and location

Question 38

___ is the most commonly muted tumor suppressor genes controlling apoptosis

Answer 38

P53