Stearic acid (C18)
Oleic acid
fatty acids
ALAEssential 3
tight packing
less stable aggregates (lower melting point)
Adipocytes showing huge fat droplets that virtually fill the cells
cotyledon cell from a seed
It contains a complex mixture of lipid that is liquid (less dense) at 37°C, begin to cristallize at 31°C and it is solid (more dense) below 31°C
Fatty acid composition of three food fats
Many fast foods are deep-fried in partially hydrogenated vegetable oils and therefore contain high levels of trans fatty acids
Triacontanoylpalmitate
waxes
Ester bond
L-Glycerol 3-phosphate, the backbone of phospholipids
Glycerophospholipids
Glycerophospholipids
Ether lipids
Hethanolammine
choline
Ether lipids
Sphingolipids
similarities in shape and molecular structure of phosphatidylcholine (a glycerophospholipid) and sphingomyelin (a sphingolipid) are clear when their space-
filling and structural formulas are drawn as here.
similarities in shape and molecular structure of phosphatidylcholine (a glycerophospholipid) and sphingomyelin (a sphingolipid) are clear when their space-filling and structural formulas are drawn as here.
The polar head of many gangliosides
Glycosphingolipids as determinants of blood groups
The specificities of phospholipases
Phospholipids and Sphingolipids Are Degraded in Lysosomes
Pathways for the breakdown of GM1, globoside, and sphingomyelin to ceramide. A defect in the enzyme hydrolyzing a particular step is indicated by the partial breakdown product is noted.
Ceramide
Sphingosine
Growth arrestApoptosis
Proliferation
IMPORTANT ALSO FOR SKIN STRUCTURE AND FUNCTION
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Necrosis: a pathological responseto cellular injury
Apoptosis: a physiological response to specific suicide signals,
or lack of survival signals
Chromatin clumps
Chromatin condenses and migrates to nuclear membrane. Internucleosomal cleavage leads to
laddering of DNA at the nucleosomal repeat length, ca. 200 bp.
Mitochondria swell and rupture Cytoplasm shrinks without membrane rupture
Plasma membrane lyses Blebbing of plasma and nuclear membranes
Cell contents spill outCell contents are packaged in membrane bounded bodies, internal organelles still functioning, to be
engulfed by neighbours.
General inflammatory response is triggeredEpitopes appear on plasma membrane marking cell
as a phagocytic target.No spillage, no inflammation
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Sphingolipids• Contain sphingosine, a long-chain amino
alcohol
• Found in plants and animals
• Abundant in nervous system
• Has structural similarity to phospholipids– Ceramide tells cells to undergo apoptosis– Sphingosine tells cells to grow, divide
and migrate Remove Phosphoethanolamine
cholesterol
A fatty acid is esterifiedFor storage ortransport
detergents in the intestine
Glycerophoepholipid that act as intracellular messengers
Arachidonic acid
Eicosanoids Carry Messages to Nearby Cells
Arachidonic acid is the precursor of eicosanoids, including the prostaglandins, thromboxanes, and leukotrienes.
PROSTAGLANDINS
stimulate contraction of the smooth muscle during menstruation and labor
Affect blood flow and wake-sleep cycle
Affect responsiveness to hormones
TROMBOXANES
Produced by plateletes, are involved in blood clot formation
Affect blood flow
LEUKOTRIENES
stimulate contraction of smooth muscles
Steroids derived from cholesterol
Many of the plant volatiles are derived from isoprene
Cholesterol is made from acetyl-CoA
• Mevalonate formation is
the first stage of cholesterol
synthesis
Mevalonate is converted to isoprene-containing molecules
• Isoprenoids are
precursors for several
important biomolecules
Vitamin D production
Vitamin A1 and its precursor and derivatives
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