Complex Lipids Sections 13.4-13.8
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Transcript Complex Lipids Sections 13.4-13.8
Complex Lipids
Sections 13.413.8
By: Cassie Webb and Alyssa
Keifer
13.4 What are the Structures of
Complex Lipids?
Main components of membranes
Classified into two groups
Phospholipids
Contain an alcohol, 2 fatty acids, and a
phosphate group
Two types
Glycerophospholipids and sphingolipids
Glycolipids
Complex lipids contain carbohydrates
13.5 What Role Do Lipids Play
in the Structure of
Membranes?
Complex
lipids form membranes around
body cells and small structures inside the
cells (organelles)
Unsaturated Fatty Acids
Lipid
molecules in bilayer contain at least
one
Prevent tight packing of hydrophobic
chains
Provides a liquid-like character to
membranes
Similar effect causes lower melting points
than saturated
Membranes
Separate cells from external environment and
provide the transportation for nutrients and
waste products into and out of the cells
Made of lipid bilayers
Two layers of complex lipid molecules arranged
tail to tail
Hydrophobic
Get as far from water as possible
Hydrophilic
On the surface
Membranes cont.
Lipid
part acts as barrier against
movement of ions or polar compounds in
or out.
Protein molecules located on the surface,
partly, or fully in the bilayer
Polar compounds transported through
protein channels or active transport.
Fluid Mosaic Model
Allows
the passage of nonpolar
compounds by diffusion
Mosaic: meaning topography of bilayers
Fluid: meaning free lateral motion in bilayers
making it liquid-like
13.6 What are
Glycerophospholipids?
Structure
similar to fats
Membrane components of cells
throughout the body
Alcohol in it is glycerol
Glycerophospholipids
Composed of
2
of 3 groups are esterified fatty acids
May be any long-chain carboxylic acids
with or without double bonds
3rd
group is esterified by a phosphate
group
Esterified to another alcohol
Letchin
Another
name
A major component of egg yolk
Both polar and nonpolar portions in one
molecule
good emulsifier
Example:
mayonnaise
Cephalins
Similar to letchins
Contain different alcohols
PI (phosphatidylinositol)
The
alcohol inositol is bonded to rest of
the molecule by phosphate ester bond
Fundamental structural parts of
membrane
In the form of PIP2 serves as a signaling
molecule in chemical communication
13.7 What are Sphingolipids?
They
were discovered in 1874 by Johann
Thudichum
Named after a monster from Greek
mythology the sphinx
A creature who devoured all who could
not provide the correct answers to the
riddles.
Properties
Alcohol
sphingosine
A long-chain fatty acid connected to NH₂
Ceramide
A combination of a fatty acid and a
sphingosine
They may use different fatty acids
Sphingomyelins
They
are the most important lipids in the
myelin sheaths of the nerve cells.
Associated with diseases
Example: multiple sclerosis
13.8 What are Glycolipids?
Complex lipids that contain carbohydrates
and ceramides
Cerebrosides are one group
They contain a ceramide mono- or
oligosaccharide
Occur primarily in the brain and nerve synapses
Gangliosides are another group
Have a more complex carbohydrate structure