Unit 2 Flashcards
Types of Proteins
Fibrous
Globular
Globular proteins
Spiral chains that are folded into spherical shapes
Insulin, hormones, enzymes
Fibrous proteins
Long spiral chains that are folded to form structures such as hair, nails, muscle tissue
Amino acids contain a link called
Amide link
Amide link looks like
O H
= |
-C-N-
Amino acids look like
O H H = | | C—C—N | | | OH R H
Where R represents a variable organic group
What happens during condensation of proteins
Amino acids join together, H20 is removed
What happens during hydrolysis of proteins
Amino acids form seperately, protein splits, H2O added
Esters just have what to as part of their reaction otherwise they cannot be produced
Acid catalyst
What makes a carboxylic avid
Oxidising agent + alcohol
Burning an alcohol produces what
CO2 and H20
What does volatile mean
Reactive
Calcium carbonate + carboxylic acid produces
Carbon dioxide
What does unsaturated mean
Carbon to carbon double bond
What is produced when fats and oils are heated with an alkali
Glycerol and soap
Soap has a ____ ____ head and a ____ _____ tail
Hydrophilic ionic
Hydrophobic non polar
Ratio of fatty acids to glycerol
3:1
What does glycerol look like
H
|
H-C-OH
|
H-C-OH
|
H-C-OH
|
HHow does soap clean
Soap dislodges the grease from the surface of the plates and the grease splits up into tiny droplets which are dispersed in the water
How are soaps made
Soaps are made by the hydrolysis of fats and oils. The fatty acids are neutralised by an alkali catalyst to form soluble ionic salts
When are detergents used
Used in areas of hard water
What is hard water
Water containing dissolved metals (Ca2positive or/and Mg2positive
What is produced when soap is used in hard water
Scum
What do detergents do that soaps cannot
Clean without producing scum
Emulsions
When two immiscible liquids are added together and shaken an emulsion is formed. MIXTURE not solution. They are sepearated
How to identify an emulsifier
E-numbers
Emulsifiers
Used in food to prevent them seperating eg mayonnaise
Same structurally as soaps and detergents
Essential oils are found in
Perfumes, cosmetics, solvents
Smell pleasant
How are essential oils extracted from plants
Steam distillation
Terpenes
Found in essential oils
What is the structural clue for identifying terpenes
Always has 5 carbons
Free radicals
Highly reactive specials containing an unpaired electron
What do antioxidants do
Mop up free radicals to protect food from spoiling and donate an electron to the potentially damaging free radical
Free radicals scavengers
Molecules that can react with free radicals to form stable molecules and prevent chain reactions
How do free radicals damage food
By removing an electron
How are free radicals produced
Oxidation reactions
Three stages of free radical chain reactions
initiation, propagation, termination
Initiation
Dividing one stable molecule produces two highly reactive radicals.
Propagation
The highly reactive radicals formed can remove atoms from other (stable) compounds to re-establish stable covalent bonds. This reaction will produce a new free radical.
Termination
The chain reaction will only end when a reaction takes place in which no new radicals are formed. This can occur whenever radicals react with each other.
What splits molecules producing free radicals
UV lights
