unit 2 Flashcards
what is UV light?
high energy form of light present in sunglight
what can UV light do to molecules?
provide sufficient energy to break bonds within molecules and free radicals are formed
what effects does UV light have on the skin?
causes subrun
accelerates ageing of the skin
what can prevent UV light reaching the skin?
use sun-block
how are free radicals formed?
when UV light energy breaks bonds within molecules
what are free radicals?
atoms or molecules that are highly reactive due to the presence of unpaired electrons
steps of a free radical chain reaction
initiation
propagation
termination
what are free radical scavengers?
molecules that react with free radicals to form stable molecules
where can free radical scavengers be found?
cosmetics
food products
plastics
what are essential oils?
concentrated extracts of the volatile, non-water soluble aroma compounds from plants
where are essential oils used?
perfumes
cosmetic products
cleaning products
flavourings in foods
what are terpenes?
isoprene units joined together
unsaturated
systematic name for isoprene?
2-methylbuta-1,3-diene
draw the structure of isoprene
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what can terpenes be oxidised to produce?
aromas of spices
what are proteins involved in?
maintenance and regulation of life processes
what are enzymes?
biological catalysts
what are proteins made of?
amino acids
what functional groups do amino acids contain?
amine group
NH2
carboxyl group
COOH
how are proteins made?
condensation
what functional group is found in a protein?
peptide link
-CONH-
what are essential amino acids?
must be required from the diet as the body cannot make them
what happens to proteins during digestion?
hydrolysis
structural formula amino acid
structural formula protein
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protein structure
long-chain molecules forming spirals held together by intermolecular bonding
what happens when a protein is heated?
intermolecular bonds are broken and proteins change shape (denature)