5 - Radiation Carcinogenesis

Question 1

What are 2 forms of radiation?

Answer 1

electromagentic and particle

Question 2

What is electromagnetic radiation?

Answer 2

waves and photons (ie: UV and x-rays)

Question 3

What is particle radiation?

Answer 3

particles and sub-particles that makeup atoms that can fly out

Question 4

Where do we get most of radiation exposure? Why?

Answer 4

radon = breaks down most radiation exposure and can go into our bodies via veggies and other food

Question 5

What is radon? Where is it commonly found in?

Answer 5

an element, abundantly found in soil

Question 6

What damage do x-rays have on DNA?

Answer 6

breaks DNA

Question 7

Why are short wavelengths more dangerous than long wavelengths of light?

Answer 7

get more of them per second

Question 8

What is the relationship of frequency with ionizing radiation?

Answer 8

as frequency and wavelength increase = increase in energy to push electrons out of orbitals

Question 9

What is indirect action of ionizing radiation?

Answer 9

flying electron = free radical &raquo_space;> grabs onto DNA electron = bond broken

Question 10

What is direct action of ionizing radiation?

Answer 10

when the electron hits DNA directly

Question 11

What are the proteins that sit on DNA?

Answer 11

histones | transcription factors | polymerases | repair enzymes

Question 12

What disease does mutations in NER cause?

Answer 12

xeroderma pigmentosum

Question 13

How cancerous are x-rays?

Answer 13

repair enzymes will effectively deal with them if minimally exposed

Question 14

What are beta particles?

Answer 14

high-velocity electrons | by-product of radioactive decay of radioactive substances

Question 15

What are alpha particles?

Answer 15

helium ions (+2 charge) | by-product of radioactive decay of radioactive substances

Question 16

What are protons and neutrons?

Answer 16

sub-atomic particles making up the nuclei of atoms

Question 17

What is radioactive decay?

Answer 17

when large atoms decay

Question 18

When large atoms undergo radioactive decay, what happens to the neutrons in the nuclei?

Answer 18

convert straight to energy (how bomb works) OR will fly out and become alpha particle

Question 19

What does LET stand for and what does it mean?

Answer 19

linear energy transfer | how much energy is transferred into environment

Question 20

Which is worse and why: high LET or low LET?

Answer 20

low LET because it is losing a lot of energy as it travels = where is that energy going in our cells? | high LET = doesn’t leave much radiation behind

Question 21

What is an example of low LET?

Answer 21

alpha particles and neutrons

Question 22

What is an example of high LET?

Answer 22

gamma rays

Question 23

What does “dose” mean?

Answer 23

how much dose is someone exposed to

Question 24

What are the 2 common radiation units used?

Answer 24

GRAY and Sieverts

Question 25

What is GRAY?

Answer 25

AMOUNT of radiation the tissue is absorbing

Question 26

What is Sieverts (Sv)?

Answer 26

what is the biological IMPACT (scale) the amount of radiation tissue is absorbing

Question 27

Which atoms are unstable?

Answer 27

those with large nuclei

Question 28

Which atom has the largest nuclei but is stable?

Answer 28

uranium

Question 29

Why is uranium important in terms of powerplants and bombs?

Answer 29

stable enough to handle and unstable enough to split easily (fission)

Question 30

What is fission?

Answer 30

splitting of an atom

Question 31

When firing a neutron at the Uranium atom results in splitting the atom, why is it the resulting pieces don't add up to the whole?

Answer 31

some of the neutrons were converted to energy

Question 32

What is a chain reaction in atom fission?

Answer 32

split of one atom = flying particles that will hit neighboring atoms = split those = cycle continues

Question 33

How fast is the atom fission chain reaction?

Answer 33

logarithmic reaction = miliseconds

Question 34

What are the buffers used to buffer neutrons?

Answer 34

uranium rods | water

Question 35

What is radiation-induced cancer?

Answer 35

cancer due to radiation exposure (ie: bombs)

Question 36

Why is getting hit with one big super hard dose of radiation better than a constant lower dose?

Answer 36

cells will get hit hard with the radiation = most likely will die

Question 37

How long do adult stem cells stay with you?

Answer 37

many decades (more than 40)

Question 38

What is instability in terms of radiation-induced cancer?

Answer 38

cells can get hit by radiation but genomic instability can be delayed due to not every type of mutation is equal

Question 39

What dictates genomic instability?

Answer 39

rate of damage and rate of mutation

Question 40

What are the 5 variables that dictate the risk for radiation-induced cancer?

Answer 40

Time (after exposure) | Age (at time of exposure) | Dose | Dose rate for low LET radiation | Quality of radiation (LET)

Question 41

If you're a cell that will be hit with radiation, when in the cell cycle would you rather get hit if not in G0? (G1, G2, S-phase, or M-phase) Why?

Answer 41

G2 | DNA repair mechanisms are at full speed ; only 1 sister chromatid will be involved