Section 1

Question 1

Explain briefly the chemical & physical effects of radiation

Answer 1

Radiation -> energy absorption in macro. -> changes in macromolecule -> bio repair -> change info of cell -> 2 -> cell/organ death or mutations -> cancer

Question 2

How does radiation affect tissue?

Answer 2

Ionisation breaks bonds ^ changing molecular fn, ejecting electrons as a result

Question 3

Direct ionisation is

Answer 3

process where radiation causes ionisation event of an atom

Question 4

Indirect ionisation is

Answer 4

when atoms are ionised by secondary electrons produced by direct ionisation

Question 5

Macromolecule is

Answer 5

large molecule like protein, carbohydrate, lipid, DNA

Question 6

Radiation + macromolecule

Answer 6

ionisation event - breaks chemical bonds and changes properties of macromolecule

Question 7

How does the radiation affect macromolecule

Answer 7

3 damage mechanisms:
1. Main Chain Scission
2. Cross Linking
3. Point Lesion

Question 8

How does main chain scission work

Answer 8

Cutting the chain into smaller branches
Effect - will not have same biochemistry as before

Question 9

How does cross linking work

Answer 9

new bonding of the structures generated - new bonds are formed to lower the e- energy

Question 10

All 3 effects can be

Answer 10

reversed through healing

Question 11

How does point lesion work

Answer 11

disruption of chemical bond but no change to macro. only modification of shape & function

Question 12

What is Gray measuring?

Answer 12

Unit for absorbed dose which is the energy absorbed over mass

Question 13

Energy absorbed is

Answer 13

What causes the damage

Question 14

What are sieverts measuring

Answer 14

Measure of health effects of low levels of radiation weighted by the type of radiation & type of tissue exposed

Question 15

Direct damage is

Answer 15

When it hits DNA

Question 16

Indirect damage hits

Answer 16

Water -> chemical change

Question 17

How do radicals affect tissue

Answer 17

Free radicals, that are unpaired electrons, cause damage as the electrons want to form bonds

Question 18

For a cell to die

Answer 18

Target molecule DNA must be hit

Question 19

How does single target hit model and multi target single hit model differ

Answer 19

Single is to simple cells (bacteria, viruses,etc) and multiple is applied to more complicated bio systems

Question 20

What does indirect damage mean

Answer 20

Radiation interacts with a medium which creates reactive chemicals and cause damaging reactions with target molecules

Question 21

Somatic mutations

Answer 21

Occur in single cell of body & cannot be inherited, causing damage to some tissue

Question 22

Genetic/germline mutations

Answer 22

Occur in gametes and can be passed on to offspring which can lead to mutations to the development of entire body

Question 23

Damaged DNA results in

Answer 23

Uncontrolled cell proliferation which is what results in cancer

Question 24

What happens to the y,

Answer 24

When I change the x variable?