Section 1 Flashcards
Explain briefly the chemical & physical effects of radiation
Radiation -> energy absorption in macro. -> changes in macromolecule -> bio repair -> change info of cell -> 2 -> cell/organ death or mutations -> cancer
How does radiation affect tissue?
Ionisation breaks bonds ^ changing molecular fn, ejecting electrons as a result
Direct ionisation is
process where radiation causes ionisation event of an atom
Indirect ionisation is
when atoms are ionised by secondary electrons produced by direct ionisation
Macromolecule is
large molecule like protein, carbohydrate, lipid, DNA
Radiation + macromolecule
ionisation event - breaks chemical bonds and changes properties of macromolecule
How does the radiation affect macromolecule
3 damage mechanisms:
1. Main Chain Scission
2. Cross Linking
3. Point Lesion
How does main chain scission work
Cutting the chain into smaller branches
Effect - will not have same biochemistry as before
How does cross linking work
new bonding of the structures generated - new bonds are formed to lower the e- energy
All 3 effects can be
reversed through healing
How does point lesion work
disruption of chemical bond but no change to macro. only modification of shape & function
What is Gray measuring?
Unit for absorbed dose which is the energy absorbed over mass
Energy absorbed is
What causes the damage
What are sieverts measuring
Measure of health effects of low levels of radiation weighted by the type of radiation & type of tissue exposed
Direct damage is
When it hits DNA
Indirect damage hits
Water -> chemical change
How do radicals affect tissue
Free radicals, that are unpaired electrons, cause damage as the electrons want to form bonds
For a cell to die
Target molecule DNA must be hit
How does single target hit model and multi target single hit model differ
Single is to simple cells (bacteria, viruses,etc) and multiple is applied to more complicated bio systems
What does indirect damage mean
Radiation interacts with a medium which creates reactive chemicals and cause damaging reactions with target molecules
Somatic mutations
Occur in single cell of body & cannot be inherited, causing damage to some tissue
Genetic/germline mutations
Occur in gametes and can be passed on to offspring which can lead to mutations to the development of entire body
Damaged DNA results in
Uncontrolled cell proliferation which is what results in cancer
What happens to the y,
When I change the x variable?
