LIPIDSLIPIDS

Important for:Important for: MembranesMembranes HormonesHormones Energy storageEnergy storage

Everyday:Everyday: Fats – solid at room temperatureFats – solid at room temperature Oils – liquid at room temperatureOils – liquid at room temperature

Three types, all contain C, H, OThree types, all contain C, H, O TriacylglycerolsTriacylglycerols PhospholipidsPhospholipids SteroidsSteroids

FUNCTIONS of FUNCTIONS of TRIGLYCERIDESTRIGLYCERIDES

Energy storageEnergy storage InsulationInsulation

Fatty AcidsFatty Acids

Long Chain hydrocarbons with a Long Chain hydrocarbons with a carboxyl terminuscarboxyl terminus

TRIACYLGLYCEROLSTRIACYLGLYCEROLS

Comprise 3 fatty acids attached to a Comprise 3 fatty acids attached to a molecule of glycerolmolecule of glycerol

TriestersTriesters

Formed by dehydration synthesis – esterification, forming an ester linkage

SaturationSaturation

Fatty acids can be SATURATEDFatty acids can be SATURATED Contain no C=C double bondsContain no C=C double bonds e.g. Stearic acid (C18), Palmitic acid (C16)e.g. Stearic acid (C18), Palmitic acid (C16)

OR UNSATURATEDOR UNSATURATED Contain a C=C double bondContain a C=C double bond Oleic acid (C18, 1 double bond)Oleic acid (C18, 1 double bond)

OR POLYUNSATURATEDOR POLYUNSATURATED Contain more than one C=C double bondContain more than one C=C double bond e.g. linoleic acid (C18, 3 C=C double bonds)e.g. linoleic acid (C18, 3 C=C double bonds)

Unsaturation introduces KINKS

The degree of saturation determines The degree of saturation determines physical propertiesphysical properties

Saturated fats pack closely together (no Saturated fats pack closely together (no kinks) – solid at room temp.kinks) – solid at room temp.

» Most animal fats are saturated – hardMost animal fats are saturated – hard

Unsaturated fats have kinks in them, cannot Unsaturated fats have kinks in them, cannot pack closely together(kinks) – liquid at pack closely together(kinks) – liquid at room temperatureroom temperature

» Most plant fats are unstauratedMost plant fats are unstaurated

SaturationSaturation

TRIACYGLYCEROLSTRIACYGLYCEROLS Triglycerides are simple or mixedTriglycerides are simple or mixed

– Simple all three fatty acids are the sameSimple all three fatty acids are the same– Mixed – contains more than one type of fatty acidMixed – 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.

PHOSPHOLIPIDSPHOSPHOLIPIDS

PhospholipidsPhospholipids Almost exclusively found in cell membranesAlmost exclusively found in cell membranes Naturally form bilipid layerNaturally form bilipid layer

cholinecholine

serineserine

ethanolamineethanolamine

Low molecular weight alcohol combined here

Based on glycerol structureBased on glycerol structureTwo fatty acid chains (esterified)Two fatty acid chains (esterified)

33rdrd alcohol group binds to a phosphate group and an alcohol group binds to a phosphate group and an alcohol e.g. choline alcohol e.g. choline

Membrane FormationMembrane Formation

Phospholipids are amphipathicPhospholipids are amphipathic– Hydrophobic (tail), & hydrophilic (head)Hydrophobic (tail), & hydrophilic (head)

Naturally form bilipid layersNaturally 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.

PhospholipidsPhospholipids

– Phosphatidyl ethanolamine (cephalins)Phosphatidyl ethanolamine (cephalins)

Most common phospholipids in animal & Most common phospholipids in animal & plant membranesplant membranes– Phosphatidyl choline (lecithins)Phosphatidyl choline (lecithins)

SteroidsSteroids

Structural variety derived from variation in side chains

CholesterolCholesterol

Essential component of membranes Essential component of membranes (eukaryotes, not prokaryotes) –(eukaryotes, not prokaryotes) –

Precursor for:Precursor for:– Adrenocorticoid hormones (e.g. cortisone),Adrenocorticoid hormones (e.g. cortisone),– Sex hormones (e.g. oestrogen, testosterone)Sex hormones (e.g. oestrogen, testosterone)– Bile acids (e.g. deoxycholic acid)Bile acids (e.g. deoxycholic acid)

GlycolipidsGlycolipids

Lipids with a carbohydrate moiety attachedLipids with a carbohydrate moiety attached