Transcript Complex Lipids

COMPLEX LIPIDS 13.4-13.8
By: Halie Derr
Nick Splitt
What are complex lipids?
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Complex lipids help to create the main components
of membranes.
Complex lipids are also referred to as compound
lipids.
They can be classified into two groups:
phospholipids and glycolipids.
What are phospholipids? (continued)
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Phospholipids contain at least one fatty acid, a
phosphate group, and sometimes a nitrogenous
base.
Two subtypes of phospholipids are
glycerophospholipids and sphingolipids.
They are one of the most important components of
a membrane.
Most phospholipids are created in the liver and
enter the bloodstream.
What are glycerophospholipids?
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Their structures are similar to that of fats.
They are membrane components of cells distributed
throughout the body.
They contain glycerol as the alcohol
Also, carbon 2 of the glycerol is always
unsaturated.
They can be broken down into three groups which
are esterified by either a fatty acid or a phosphate
group which is esterified by another alcohol.
What are glycerophospholipids?
(continued)
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If the alcohol choline is used phosphatidylcholines
(lechtin) is created.
 Lechtin
usually contains linoleic acid in the middle and
stearic acid on the end.
 Lechtin is a major component of egg yolk, a good
emulsifier, and found in mayonnaise.
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If an alcohol such as ethanolamine or serine is used
it will create cephalins which are very similar to
lechtins.
What are glycerophospholipids?
(continued)
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When the alcohol inositol is bonded to a molecule
by a phosphate ester bond Phosphatidylinositols (PI)
is created.
They can be found in biological membranes and can
be used as signaling molecules for chemical
communication.
(Purple indicates the different alcohols)
What are sphingolipids?
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Johann Thudichum discovered sphingolipids in 1874
and named them after the Sphinx.
When hydrolyzed, sphingosine substitutes for
glycerol in these lipids.
They are common membrane components because
they have both hydrophilic and hydrophobic
characteristics.
Ceramide is a combination of a fatty acid and
sphingosine.
Ceramides are found in sphingolipids.
How do sphingomyelins help in the
myelin sheath?
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Myelin sheaths, the coating of nerve axons in the
brain, contain different complex lipids, one of them
being sphingomyelins.
Sphingomyelins are the most important lipids in the
myelin sheaths of nerve cells.
 They
are associated with diseases such as multiple
sclerosis.
What are glycolipids?
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Glycolipids are complex lipids that contain
carbohydrates and ceramides
There are several different groups of glycolipids, such
as gangliosides and cerebrosides
Gangliosides have a more complex carbohydrate
structure
Cerebrosides contain mono- or oligosaccharides.
They occur mainly in the brain, accounting for 70% of the
brains dry weight and at nerve synapses.
 The fatty acid of the ceramide part of the cerebroside
contains 18 to 24 carbon chains.
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What are membranes?
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Made up of lipid bilayers
A lipid bilayer is a two-layered structure of complex
lipids set tail to tail.
Hydrophobic tails point towards each other
Hydrophilic heads point out from each other enabling
them to be close to water.
Membranes have liquid like characteristics because the
unsaturated fatty acids prevent tight packing in the
lipid bilayer.
An important component of a membrane is cholesterol.
Cholesterol has a similar structure to other membranes
What role do lipids play in the
structure of membranes?
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Complex lipids form membranes around organelles
which are small structures inside the cells.
They provide selective transport for nutrient and
waste products into and out of cells.
In addition, they separate cells from their external
environment.
An important component of complex lipids are the
unsaturated fatty acids especially in the lipid
bilayer.