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Biological molecules
- Water
- Vital to living organisms
- Reactant in
many important
chemical
reactions,
- Solvent as
most reactions
happen in
solution
- Transports
substances
- Carries away energy
when evaporating so it
helps cools things down
- Reactant in
many important
chemical
reactions,
- Simple structure
- Polar molecule: One
delta -ve oxygen and
two delta +ve
hydrogens
- Polar molecule: One
delta -ve oxygen and
two delta +ve
hydrogens
- Properties
- Hydrogen bonds
give a high specific
heat capacity
- A lot of energy
to raise the temp
by 1degree
- A lot of energy
to raise the temp
by 1degree
- Hydrogen bonds
give a high latent
heat of evaporation
- Polarity
makes it
cohesive
- Polarity makes
it a good
solvent
- Hydrogen bonds
give a high specific
heat capacity
- Vital to living organisms
- Proteins
- Made from long chains
called polypeptides. A
protein is made up of one or
more polypeptide chains
- They all have the same
structure: carboxyl group
(-COOH), an amino group
(-NH2) and a carbon atom
and a variable group
- Peptide bonds: A water molecule is
released during the reaction and the
reverse adds a molecule of water to
break the peptide bond
- Structural levels and bonds
- Primary: Sequence
of amino acids.
(Peptide bonds)
- Secondary: Alpha
helix and beta sheets
(hydrogen bonds)
- Tertiary: Coiled and folded
more into a 3D structure ( Ionic
bonds, disulphide bridges,
hydrogen bonds and
hydrophobic interactions)
- Quaternary: Multiple
polypeptide chains join
together (all the bonds in
tertiary)
- Primary: Sequence
of amino acids.
(Peptide bonds)
- Collagen is a fibrous
protein. Supportive tissues
in animals and is strong.
Three polypeptides, tightly
coiled. Interlinked by
covalent bonds
- Haemoglobin is a globular
protein. Iron containing haem
group. Hydrophilic side chains
and hydrophobic side chains
face inwards. Soluble in water
so its good for transport
- Haemoglobin is a globular
protein. Iron containing haem
group. Hydrophilic side chains
and hydrophobic side chains
face inwards. Soluble in water
so its good for transport
- Made from long chains
called polypeptides. A
protein is made up of one or
more polypeptide chains
- Carbohydrates
- Carbohydrates are
made from
monosaccharides
either beta or alpha.
- They are soluble so it can be
transported as it is the main
energy source in plants and
animals. Chemical bonds
contain a lot of energy
- They are soluble so it can be
transported as it is the main
energy source in plants and
animals. Chemical bonds
contain a lot of energy
- Glycosidic bonds
- Water is released and to
break the bonds add water
- Water is released and to
break the bonds add water
- Starch (main energy storage in
plants). Amylose is long,
unbranched alpha glucose. Coiled
so it can fit into small places.
Starch is insoluble so it is good for
storage. 1-4 glycosidic bonds
- Glycogen (main energy
storage in animals).
Branched, alpha glucose,
good for quick release of
energy. Also very compact
and insoluble. 1-6 glycosidic bonds
- Cellulose (major component in cell walls
in plants). Made from long, unbranched,
beta glucose. Bonds are straight.
Cellulose chains are linked by hydrogen
bonds. Provide structural support. 1-4
gylcosidic bonds
- Cellulose (major component in cell walls
in plants). Made from long, unbranched,
beta glucose. Bonds are straight.
Cellulose chains are linked by hydrogen
bonds. Provide structural support. 1-4
gylcosidic bonds
- Glycogen (main energy
storage in animals).
Branched, alpha glucose,
good for quick release of
energy. Also very compact
and insoluble. 1-6 glycosidic bonds
- Carbohydrates are
made from
monosaccharides
either beta or alpha.
- Lipids
- Trigylcerides
- One glycerol molecule,
three fatty acids
(hydrophobic) and three
ester bonds. Insoluble
- Hydrocarbon tails contain lots
of chemical energy so they are
insoluble. Don't allow water in
as it would swell. Triglycerides
bundle together, fatty acid tails
inside, as a storage molecule
- One glycerol molecule,
three fatty acids
(hydrophobic) and three
ester bonds. Insoluble
- Phospholipids
- One glycerol
molecule, two
fatty acids
(hydrophobic),
one phosphate
group
(hydrophilic)
- Make up the bilayer in cell
membranes, controls what
enters and leaves
- One glycerol
molecule, two
fatty acids
(hydrophobic),
one phosphate
group
(hydrophilic)
- Cholesterol
- Hydrocarbon rings,
hydrocarbon tail and
a hydroxyl group
makes it soluble.
- Strengthens the cell
membrane by making is less
fluid and more rigid. Make them
packed closer together
- Hydrocarbon rings,
hydrocarbon tail and
a hydroxyl group
makes it soluble.
- Trigylcerides
- Tests for molecules
- Benedicts test
for sugars
- Reducing sugars: Add
benedicts test and heat.
From blue to brick red
- Non reducing sugars: Boil with
dilute HCl and neutralise with
NaHCO3, then do benedicts test
- Non reducing sugars: Boil with
dilute HCl and neutralise with
NaHCO3, then do benedicts test
- Reducing sugars: Add
benedicts test and heat.
From blue to brick red
- Iodine test for
starch, from
brown/orange to
blue/black
- Biurets for proteins
- Add sodium
hydroxide, then
copper sulfate. From
blue to purple
- Add sodium
hydroxide, then
copper sulfate. From
blue to purple
- Emulsion for lipids:
Shake with ethanol
and then pour into
water. White
emulsion ontop
- Benedicts test
for sugars
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