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CHAPTER 11: Lipids
Olive trees
provide a
healthy
source of oil
for our diet
although
unprocessed
fruit is
inedible.
What is the composition of olive oil?
Lipids
Water insoluble (hydrophobic)
Non-polymeric structure
Energy storage, membrane
constituent, hormone signaling
Migrate over-water 2,400 miles
I. Fatty Acids: Fuel & Membrane
Building Blocks
Hydrocarbon with carboxylic acid head group
Soap: fatty acid salt
Highly reduced carbon source
Ionized at neutral pH (-ate not -ic acid form)
Which fatty acid is more reduced?
What makes soap a good cleaner?
Fatty Acid Conventions
The positions of double bonds are indicated with the symbol Δ, with
the first atom of the double bond indicated by superscript number.
Δ9 indicates a double bond between carbon atoms 9 and 10.
Because fatty acids are ionized at physiological pH, they are usually
referred to as their carboxylate form, rather than the unionized acid.
Naturally Occurring Animal Fatty
Acids: Common and Systemic Names
Melting Point and Membrane Fluidity
Shorter chain length lowers
melting point
cis Double bond lowers
melting point
Unsaturated fatty acids (oils)
lower melting point versus
saturated fatty acids (solid)
Predict the oil
composition from
palm versus canola
plants.
Health Versus Fat Quantity and Quality
Trans fats correlated with high
blood cholesterol/cardiovascular
disease (inflammation?)
Cis polyunsaturated fatty acids
essential for the diet (inhibit blood
clotting, reduce heart attack risk)
Vegetable oil (linolenate)
Shell fish/cold water fish
(EPA/DHA)
II. Triacylglycerol in Energy Storage
Anhydrous fat /gram stores 6x energy of hydrated glycogen
Triacylglycerol storage site – adipose tissue
Sugar storage 18 hrs; triacylglycerol
storage several weeks
Phospholipids, Glycolipids and Steroids
What do these lipids have
in common?
How do these lipids differ?
III. Phospholipids: Major Class of
Membrane Lipids
Phosphatidate: key
intermediate in
phosphoglyceride
biosynthesis and
membranes
Common Membrane Phosphoglycerides
What does the
color coding for
green, blue and
pink represent?
Membrane Sphingolipids
Amino alcohol backbone – sphingosine
Sphingomyelin –
sphingosine with a fatty acid
amide linkage and choline;
abundant in nerve cell
membranes
trans
double bond
Cerebroside – sphingosine
with one sugar residue is the
simplest type of glycolipid
IV. Glycolipids
Gangliosides – sphingosine
with multiple sugar residues
Sugars are extracellular
A, B and O blood typing
Multiple
sugar units
V. Steroids
Tetracyclic ring structure
(3 cyclohexane fused with
cyclopentane)
Facilitate lipid digestion
Membrane fluidity buffer
How does cholesterol
orientate in the
membrane?
Lipoproteins
Protein attachments to the surface of a membrane
Membrane Component from a HighTemperature Organism
What are the chemical differences in this lipid from
standard membrane lipids?
What impact do these alterations have on lipid behavior?
Chapter 11 Problems: 1-19
Workbook page 58: 2-9 due April 2