(Midterms) IR Interactions Flashcards
1
Q
Occurs as a result of ionization of atoms on essential molecules (DNA, macromolecules, chromosomes)
A
Biological damage
2
Q
Cell lethality: To describe non lethal radiation, induce —
A
cell abnormalities
3
Q
Direct effect (Cell theory) could lead to either (1) or (2)
A
- activation
- alteration
4
Q
DNA needs to experience a hit for an effect, specifically —, to occur
A
cell abnormalities
5
Q
High LET radn is an example of what molecular effect of radn?
A
Direct Effect
6
Q
Area of the cell occupied by the target molecule or by the sensitive site on the target molecule
A
Target (Nucleus, specifically DNA)
7
Q
Why does direct effect happen discretely and in random?
A
Because anatomically, the nucleus roams around because of the presence of cytosol. It does NOT stay in the middle
8
Q
Product: absorption of energy (photoelectric and compton interactions)
A
Direct Effect (Molecular effect of radn)
9
Q
Cell death could happen in 2 ways
A
- In vivo
- In vitro
10
Q
Irradn within the body
A
In vivo
11
Q
Macromolecules are radiosensitive if they are in their natural state (not altered)
A
In vivo
12
Q
Irradn outside of the body
A
In vitro
13
Q
A threshold dose should be reached for a measurable effect to occur
A
In vitro
14
Q
Produced by free radicals that are created by the interaction of radn and water molecule
A
Indirect effect
15
Q
Human body consists of (1) water and (2) DNA
A
- 80%
- 1%
16
Q
Free radicals w their excess energy of reaction are the intermediate molecules
A
Indirect effect
17
Q
They are going to migrate to the target molecule and transfer their energy, which will result to damage.
A
Indirect effect
18
Q
Always unstable, always causes damage (bond breaks)
A
Free radicals
19
Q
Radiolysis of water is an example of what molecular effect of radn? (1)
It happens specifically where?
A
- Indirect effect
- In vivo
20
Q
Radiolysis of water should produce (1) and (2) at the end of the process
A
- ion pairs
- free radicals
21
Q
3 types of ions produced in radiolysis of water
A
- electron
- HOH+
- HOH-
22
Q
Represents principal radn interaction in the body
A
Indirect effect/ Radiolysis of water
23
Q
When water is irradiated, it is ionized and dissociates into two ions called —
A
ion pairs
24
Q
Product of initials ionization of radiolysis
A
HOH+ + electron
25
What happens after initial ionization in radiolysis?
1. Ion pair may rejoin = stable water molecule (HOH+ + e- = H2O) ; NO DAMAGE
2. Ions won't rejoin = e- + H2O = HOH- (3rd type of ion)
26
Dissociation of the unstable ions
HOH+ --> H+ + OH*
HOH- --> OH- + H*
27
Final result of radiolysis of water
Ion pair, H+ and OH-
2 free radicals, H* and OH*
28
Uncharged molecule that contains a single unpaired e- in the outer shell but no bet electric charge
Free radicals
29
Free radicals occur when there is (1) as they make the cells (2)
1. water
2. radiosensitive
30
Free radicals lifespan
less than 1msec
31
Reaction that will form HOH (Unstable water molecule)
OH* + H*
32
Reaction that will form H2O2 (Hydrogen Peroxide)
OH* + OH*
33
Reaction that will form HO*2 (Hydroperoxyl radical)
H* + O2
34
Reaction that will form H2O2 + O2 (Hydrogen Peroxide)
HO* 2 + HO* 2
35
Reactions that will form Organic Free Radicals
1. RH + IR = H* + R*
2. R* + O2 = RO*2
36
Irradn of Macromolecules happens ---
in vitro
37
Major effects when macromolecules are irradiated in soln in vitro
1. Main chain scission
2. Cross-linking
3. Point Lesions
38
Breakage of backbone of the long-chain macromolecule
Main chain scission
39
Main chain scission results
1. Reduction in size (long chain to short chain)
2. Reduction in viscosity
40
Macromolecules have small, spurlike side structures that extend off the main chain
Cross-linking
41
Behave as though they had a sticky substance on the end and attach to a neighboring macromolecule or to another segment of the same molecule
Side structures (Cross-linking)
42
Cross-linking results
Increased viscosity
43
Disruption of single chemical bond
Point Lesions
44
At low radn dose, these are considered to bethe cellular radn damage that results in the stochastic radn effects observed at the whole-body level
Point Lesions
45
Its effect is not detectable, but could cause a minor modification of molecule, causing malfunction within the cell
Point Lesions
46
Nutrients will be brought to the cell and diffused and released as energy
Catabolism
47
Small energies will create another set of protein (small energy --> ribosomes = protein)
Anabolism
48
Reduction of nutrient molecules for energy
Catabolism
49
Production of large molecules for form and function
Anabolism
50
Processes under anabolism
1. Transcription
2. Transfer
3. Translation
51
Review transcription, transfer, and translation from genetic material to protein
52
Radn damage to any of the macromolecules during protein synthesis could lead to (1) or (2)
1. cell death
2. late stochastic effect
53
Only one in the body that is continuously synthesized, making them abundant and present all the time
Proteins
54
Proteins are more (1) and less (2) than nucleic acid
1. abundant
2. radiosensitive
55
If radn damage to the DNA is severe enough, visible --- may ne detected
Chromosome aberrations/ Cytogenic damage
56
Chromosome aberrations/ Cyrogenic damage
1. Deterministic/ Non-stochastic effect
2. Stochastic/ Probabilistic effect
3. Genetic effect
57
If enough cells of the same type respond similarly, then a particular organ can be destroyed that describe the caise of this effect
Deterministic/ Non-stochastic Effect
58
Uncontrolled rapid proliferation of cell is the principal characteristic of radn indiced malignant disease
Stochastic/ Probabilistic Effect
59
If damage to the DNA occurs within a germ cell, it is possible that the response to radn expo will not be observed until the following generation or even later
Genetic effect
60
Signals the start and end of a protein synthesis
Codon
61
Other terms for codon
Triplet code/ three base pairs
62
Rupture 1 chemical bond and possible breakage in one of the sugar phosphate chain side rails/ strand of the ladderlike DNA structure
Main chain scission with one side rail severed
63
Main chain scission with one side rail severed is also called (1) or (2)
1. Single strand break
2. Point mutations
64
Repair is possible to this/these radn response of DNA (reversible)
1. Main chain scission with one side rail severed
65
Occur in Low LET radn
Main chain scission with one side rail severed
66
Important factor in assessing potential tissue/ organ damage
Main chain scission with one side rail severed
67
Rupture two chemical bond and possible breakage if the sugar phosphate chain side rails/strand of the ladderlike DNA structure
Main chain scission with both sides rail severed
68
Complete breakage of chromosome
Main chain scission with both sides rail severed
69
Occur in high LET radn
Main chain scission with both sides rail severed
70
Main chain scission with both sides rail severed is also called as ---
Double strand break
71
Effects:
1. Cell death/ impaired function
2. Cleaved cell (separation, division)
Main chain scission with both sides rail severed
72
Passed down to daughter cells; daughter cells will receive incorrect amount of genetic material
Main chain scission with both sides rail severed
73
Cause is high energy radn with DNA molecule
Mutation
74
Results in alteration of nitrogenous bases
Mutation
75
If viable, incorrect genetic information will be transferred to 1 of the 2 daugter cells
Mutation
76
Sometimes reversible but oftentimes irreversible as they could cause acute consequences
Mutation
77
Repair is not possible to this/these radn response of DNA (irreversible)
1. Main chain scission with both sides rail severed
2. Covalent cross links
78
After irradn, molecules can fragment or change into small, spurlike structures than become very interactive (sticky) to other molecules
Covalent Cross Links
79
Types of covalent cross-links
1. Bn 2 places on the same DNA strand (Intrastrand crosslink)
Interstrand crosslink
2. Bn 2 DNA strand
3. Bn 2 DNA molecules
80
Causing a separation of bases
Rung breakage
81
Loss/ change in the nitrogenous bases im the DNA chain, resulting to sequence alteration
Rung Breakage
82
Categories of Chromosome Irradn
1. Radn-Induced Chromosome Breaks
2. Chromosome Fragments
3. Chromosome Anomalies
83
Viewed microscopically
Radn-Induced Chromosome Breaks
84
Manifest during metaphase and anaphase because the length of the chromosome is still visible
Radn-Induced Chromosome Breaks
85
Gross/ visible differences in the structure
Radn-Induced Chromosome Breaks
86
Occur in(?) somatic and reproductive cells
Radn-Induced Chromosome Breaks
87
After chromosome breakage, 2 or more fragments are produced
Chromosome fragments
88
Broken ends are chemically very reactive and adhere to another similar sticky end
Chromosome fragments
89
May:
1. Rejoin to the original configuration
2. Fail to rejoin and create an aberration
3. Join other broken ends and create new chromosomes
Chromosome fragments
90
Types of chromosome anomalies
1. Chromosome aberrations
2. Chromatid aberrations
91
Chromosome anomaly that happens in early interphase
Chromosome aberrations
92
Break: single strand of chromatid
Chromosome aberrations
93
Result: irradn of individual chromatid
Chromatid aberrations
94
Chromosome anomaly where 1 daughter cell is affected
Chromatid aberrations
95
Structural changes in Biological Tissues (as result of radn expo)
1. Single strand break in 1 chromosome
2. Strand break in 1 chromatid
3. Single strand break in separate chromosomes
4. Strand break in separate chromatids
5. More than 1 break in same chromosome
6. More than 1 break in same shromatid
7. Chromosome stickiness
96
Consequences to the cell from structural changes in biological tissue
A. Single Break Effect
1. Restitution
2. Acentric chromosome
3. Dicentric chromosome
4. Translocation
B. Double Break Effect
1. Deletion
2. Inversion
3. Acentric chromosome
4. Dicentric chromosome
5. Ring chromosome
C. Chromosome stickiness
97
Rejoining and healing of the broken ends of the chromosomes
Restitution
98
No cell damage occurred
Restitution
99
Joining of 2 chromatids without a centromere
Acentric chromosome
100
Joining of 2 chromatids with a centromere
Dicentric chromosome
101
Joining acentric fragments from 1 chromosome to the fragment containing the centromere of the other chromosome
Translocation
102
Broken-snd arrangement without visible damage to the chromatids
Translocation
103
Fragment bn break is removed
Deletion
104
Deleted fragments from deletion are lost during ---
cell division
105
Acentric fragment will rejoin with the fragment with a centromere to form a normal-loolint chromosome but lacking in genetic material
Deletion
106
Fragment with broken ends turn around and rejoin thereby rebersing its position on the chromosome
Inversion
107
Chromosome appears normal, however, the sequence of the bases has been altered
Inversion
108
Results when broken ends of the fragments with the centromere moves about and twist before rejoining
Ring chromosome
109
Single break effect vs double break effect
Single break effect: only 1 beam hits the chromosome
Double break effect: 2 xr beams hit the chromosome
110
Deletion vs inversion
Deletion: lacks DNA info
Inversiom: DNA is altered
111
Chromosome appear to clump together
Chromosome stickiness
112
Chromosome stickiness occur during what phase/s?
Metaphase and anaphase
113
At metaphase and anaphase, the chromosome appear to clump together. This clumping could result to an error in the ---
transmission of genetic info to the daughter cells
114
Believed to be caused by the alteration in the chemical composition of the protein component of the chromosome by irradn
Chromosome stickiness
115
Most radiosensitive part of cell
DNA
116
Carries teh genetic material of the cell
DNA
117
Controls growth and development of a cell
Chromosome
118
