Lipids - created from Mind Map

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Fatty Acids

Triglycerides

Waxes

Polar Lipids

Membrane Lipids

Carboxylic Acids with hydrocarbon chains containing between 4-36 carbons.

Saturated: no double bonds between carbons in the chain

Unsaturated

Natural fatty acids have an even Number of Carbons and are unbranched.

Pack in an orderly way - extensive favorable interactions especially van der waals

Two types:

Trans Fatty Acid

Cis Fatty Acid

Polyunsaturated: more than one double bond in the alkyl chain

Monounsaturated: one double bond between the carbons in the alkyl chain

Formed due to partial hydrogenation of vegetable oils which raise LDL and increase inflammination respose

Trans double bond allows a given fatty acid to adopted extended conformation

This means they are packed more regularly and therefore have a higher melting point than cis forms

Help prevent tight packing in biological molecules

This keeps the membranes more fluid - the degree of unsaturation in the fatty acid chain has affect on membrane fluidity. The more double bonds the more fluid.

It takes less thermal energy to disrupt disordering packing of unsaturated fatty acids therefore unsaturated cis fatty acids have a lower melting point.

Non-polar

Solid ones are fats and liquid ones are oils

Majority of lipids found in this form

Less soluable in water than fatty acids due to the lack of charged carboxyolate groups

Glycerol is esterified to 3 fatty acids

Primary storage form of lipids (body fat)

Less dense than water: fats and oils float

Esters of long chained saturated and unsaturated fatty acids with long chain alcohols

Insoluble and have high melting points

Variety of functions

storage of metabolic fuel in plankton

Protection and pliability of hair and skin in vertebrates

waterprofing of feathers in birds

Protection from evaporation in tropical plants and ivy

Used by people in lotions, ointments and polishes

Contain polar head and non-polar tail

Diversication

Amphipathetic

Also form micells, bilayers and liposomes

Major component of biological membrane

Modifying a different backbone

Changing the fatty acid

Modifying the head groups

Contains both hydrophobic and hydrophilic groups

Polar heads and 2 polar tails

Polar lipids replace one of the fatty acids with polar group which means that the new polar group allows more solubility in water

Glycerophospholipids

Phosphatidylcholine

Sphingolipids

unsaturated fatty acids often found connected to carbon 2

The highly polar phosphate group may be further esterifed by an alcohol such groups are called head groups.

major component of most eukaryotic cell membranes

Many prokaryotes can synthesise this lipid

Backbone is not glycerol it is a long chain amino alcohol sphingosine

Found in the outer surface of plasma membranes

Sphingomyelin

Joined via amide linkage opposed to ester

Polar head is connected to sphingosine via glycosidic or phosphodiester linkage

Ceramide (sphingosine +amide-linked fatty acid) + phosphocholine attached to the alcohol

Abundant in myelin sheath that surrounds some nerve cells in animals