LIPIDS

Important for:




Everyday:



Membranes
Hormones
Energy storage
Fats – solid at room temperature
Oils – liquid at room temperature
Three types, all contain C, H, O



Triacylglycerols
Phospholipids
Steroids
FUNCTIONS of
TRIGLYCERIDES
Energy storage
 Insulation

Fatty Acids
Long Chain hydrocarbons with a
carboxyl terminus
TRIACYLGLYCEROLS

Comprise 3 fatty acids attached to a
molecule of glycerol

Triesters
Formed by dehydration synthesis –
esterification, forming an ester linkage
Saturation
Unsaturation introduces KINKS
 Fatty acids can be SATURATED



OR UNSATURATED



Contain no C=C double bonds
e.g. Stearic acid (C18), Palmitic acid (C16)
Contain a C=C double bond
Oleic acid (C18, 1 double bond)
OR POLYUNSATURATED


Contain more than one C=C double bond
e.g. linoleic acid (C18, 3 C=C double bonds)
Saturation
The degree of saturation determines
physical properties
 Saturated fats pack closely together (no
kinks) – solid at room temp.

» Most animal fats are saturated – hard

Unsaturated fats have kinks in them, cannot
pack closely together(kinks) – liquid at
room temperature
» Most plant fats are unstaurated
TRIACYGLYCEROLS

Triglycerides are simple or mixed
– Simple all three fatty acids are the same
– Mixed – contains more than one type of fatty acid
In 1860, Fredrick Walton invented linoleum the home floor covering.
In 1860, rubber manufacturer Fredrick Walton invented linoleum the floor covering used
in Victorian homes. Three years later, Walton received an English patent for linoleum.
Walton was inspired to invent linoleum as a cheap substitute for a more expensive
rubber composition called Kamptulicon. He got the idea from observing the skin on
oxidized linseed oil that forms on paint.
Linoleum is made of linseed oil, pigments, pine rosin and pine flour. Linoleum is
manufactured by oxidizing linseed oil and adding the other ingredients to form a thick
mixture called linoleum cement. The name linoleum comes from the Latin word, linum,
which means flax, and oleum, which means oil. Linoleum was later replaced in
popularity by vinyl floor coverings of the 1960s.
Linoleum was later perfected by Scottish flooring manufacturer Michael Nairn, who
introduced the inlaid patterning that linoleum is known for.
Together with fellow inventor Fredrick Thomas Palmer, Fredrick Walton later invented
Anaglypta and Lincrusta. Anaglypta and Lincrusta are two forms of Victorian-era
embossed home wall coverings. Lincrusta is made of a linseed oil mixture and
Anaglypta is made from cotton pulp.
PHOSPHOLIPIDS

Phospholipids


Low molecular
Almost exclusively found in cell membranes
weight alcohol
Naturally form bilipid layer
combined here
Based
on glycerol structure
Two
fatty acid chains (esterified)
3rd
alcohol group binds to a phosphate group and an
alcohol e.g. choline

choline
ethanolamine
serine
Membrane Formation

Phospholipids are amphipathic
– Hydrophobic (tail), & hydrophilic (head)

Naturally form bilipid layers
Because membranes contain lipids,
Fat soluble molecules e.g steroid hormones can pass straight
through them. Receptors for these hormones found in cytosol.
Phospholipids

Most common phospholipids in animal &
plant membranes
– Phosphatidyl choline (lecithins)
– Phosphatidyl ethanolamine (cephalins)
Steroids
Structural variety derived from variation in
side chains
Cholesterol
Essential component of membranes
(eukaryotes, not prokaryotes) –
 Precursor for:

– Adrenocorticoid hormones (e.g. cortisone),
– Sex hormones (e.g. oestrogen, testosterone)
– Bile acids (e.g. deoxycholic acid)
Glycolipids

Lipids with a carbohydrate moiety attached