1.1 Chemical elements are joined together to form
biological compounds
(a) the key elements present as inorganic ions in living organisms: Mg 2+, Fe2+,
Ca2+, PO 3–
4
(b) the importance of water in terms of its polarity, ability to form hydrogen
bonds, surface tension, as a solvent, thermal properties, as a metabolite
(c) the structure, properties and functions of carbohydrates: monosaccharides
(triose, pentose, hexose sugars); disaccharides (sucrose, lactose, maltose);
polysaccharides (starch, glycogen, cellulose, chitin)
(d) alpha and beta structural isomerism in glucose and its polymerisation into
storage and structural carbohydrates, illustrated by starch, cellulose and chitin
(e) the chemical and physical properties which enable the use of starch and
glycogen for storage and cellulose and chitin as structural compounds
(f) the structure, properties and functions of lipids as illustrated by triglycerides
and phospholipids
(g) the implications of saturated and unsaturated fat on human health
(h) the structure and role of amino acids and proteins
(i) the primary, secondary, tertiary and quaternary structure of
proteins
Primary – sequence of amino acids held by peptide bonds
Secondary – initial folding of polypeptide chain held by hydrogen bonds,
forming -helix or -pleated sheet
Tertiary – further folding of secondary structures due to R group
interactions/ ionic/ covalent/ S-S bridges/ hydrogen bonds/ hydrophobic
interactions
Quaternary – more than one polypeptide chain held together
(j) the relationship of the fibrous and globular structure of proteins to
their function
Fibrous Globular
Properties Insoluble Soluble
Elongated/ long/ rods/ filament/ Spherical/ ball-shaped
ropes/ strands 3D/ tertiary structure
Strong/ tough Ref. conjugated, contain
Flexible prosthetic group
Temperature/ pH sensitive
, Hydrophilic on outside
Functions structure enzymes/ metabolic role/ to
catalyse reactions/ to lower
o collagen in bone/ activation energy
cartilage/ connective
tissue/ tendons/ o named enzyme +
ligaments/ skin/ blood specific role
vessels
o fibrin + role described hormones/ receptors/ for cell
signalling
protection
o names hormone/
o keratin in skin/ hair/ insulin + role
nails described
to give elasticity/ elastic antibody/ for immunity/
properties defence against infection
o elastin in blood vessels/ o opsonin/ antitoxin/
alveoli/ cartilage agglutinin + role
described
contraction/ mechanical o fibrinogen in blood
movement clotting
o actin/ myosin, in muscle transport substances across
o microtubules in cilia/ cell membrane
flagella/ spindle/
cytoskeleton o carrier/ channel pump
+ role described
transport substances in blood
o haemoglobin + role
described eg. carry
oxygen
to package/ organise DNA
Learners should be able to use given structural formulae (proteins, triglycerides
and carbohydrates) to show how bonds are formed and broken by condensation
and hydrolysis, including peptide, glycosidic and ester bonds.
(Learners should be able to recognise and understand but not reproduce the
structural formulae of the above molecules.)
SPECIFIED PRACTICAL WORK
2
biological compounds
(a) the key elements present as inorganic ions in living organisms: Mg 2+, Fe2+,
Ca2+, PO 3–
4
(b) the importance of water in terms of its polarity, ability to form hydrogen
bonds, surface tension, as a solvent, thermal properties, as a metabolite
(c) the structure, properties and functions of carbohydrates: monosaccharides
(triose, pentose, hexose sugars); disaccharides (sucrose, lactose, maltose);
polysaccharides (starch, glycogen, cellulose, chitin)
(d) alpha and beta structural isomerism in glucose and its polymerisation into
storage and structural carbohydrates, illustrated by starch, cellulose and chitin
(e) the chemical and physical properties which enable the use of starch and
glycogen for storage and cellulose and chitin as structural compounds
(f) the structure, properties and functions of lipids as illustrated by triglycerides
and phospholipids
(g) the implications of saturated and unsaturated fat on human health
(h) the structure and role of amino acids and proteins
(i) the primary, secondary, tertiary and quaternary structure of
proteins
Primary – sequence of amino acids held by peptide bonds
Secondary – initial folding of polypeptide chain held by hydrogen bonds,
forming -helix or -pleated sheet
Tertiary – further folding of secondary structures due to R group
interactions/ ionic/ covalent/ S-S bridges/ hydrogen bonds/ hydrophobic
interactions
Quaternary – more than one polypeptide chain held together
(j) the relationship of the fibrous and globular structure of proteins to
their function
Fibrous Globular
Properties Insoluble Soluble
Elongated/ long/ rods/ filament/ Spherical/ ball-shaped
ropes/ strands 3D/ tertiary structure
Strong/ tough Ref. conjugated, contain
Flexible prosthetic group
Temperature/ pH sensitive
, Hydrophilic on outside
Functions structure enzymes/ metabolic role/ to
catalyse reactions/ to lower
o collagen in bone/ activation energy
cartilage/ connective
tissue/ tendons/ o named enzyme +
ligaments/ skin/ blood specific role
vessels
o fibrin + role described hormones/ receptors/ for cell
signalling
protection
o names hormone/
o keratin in skin/ hair/ insulin + role
nails described
to give elasticity/ elastic antibody/ for immunity/
properties defence against infection
o elastin in blood vessels/ o opsonin/ antitoxin/
alveoli/ cartilage agglutinin + role
described
contraction/ mechanical o fibrinogen in blood
movement clotting
o actin/ myosin, in muscle transport substances across
o microtubules in cilia/ cell membrane
flagella/ spindle/
cytoskeleton o carrier/ channel pump
+ role described
transport substances in blood
o haemoglobin + role
described eg. carry
oxygen
to package/ organise DNA
Learners should be able to use given structural formulae (proteins, triglycerides
and carbohydrates) to show how bonds are formed and broken by condensation
and hydrolysis, including peptide, glycosidic and ester bonds.
(Learners should be able to recognise and understand but not reproduce the
structural formulae of the above molecules.)
SPECIFIED PRACTICAL WORK
2
