UV light and skincare Flashcards
What is UV light?
High energy form of light present in sunlight.
Three types of UV light -
UVA, UVB, UVC
Effect of UV light on molecules -
UV light can provide enough energy to break covalent bonds between atoms forming free radicals
How are free radicals represented?
Cl+ (+=.)
Free radicals are …..
Atoms or molecules that are highly reactive atoms are molecules due to the presence of unpaired electrons
Due to the free radicals being unstable, what will often happen?
They will react very quickly to pair up the electron, this process will involve a new free radical often being produced.
This will cause a chain reaction as this process will repeat itself
What to remember when drawing initiation reaction
UV light above arrow
Types of chain reaction reactions -
Initiation, Propagation, Termination
Initiation reaction
Splitting of a covalent bond by the energy from UV light producing two free radicals each with one unpaired electron
Propagation reaction
Reaction between normal molecule and free radical generating one new free radical and a normal molecule
Termination reaction
When two free radicals react forming a stable molecule, this will end the chain reaction.
Dangers of UV light
Can cause skin cancer or sunburn or aging of skin
How does sunblock prevent damage from UV light?
By reflecting or absorbing UV light
Free radical scavengers
Molecules that react with free radicals to form stable molecules and preventing chain reactions.
Example of free radical scavenger
Antioxidant since they give away electrons while being oxidised
Example - ascorbic acid
