Transcript Apoptosis
Stearic acid (C18) Oleic acid w3 fatty acids ALA Essential w3 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 waxes Ester bond Triacontanoylpalmitate L-Glycerol 3-phosphate, the backbone of phospholipids Glycerophospholipids Glycerophospholipids Ether lipids H ethanolammine Ether lipids choline Sphingolipids similarities in shape and molecular structure of phosphatidylcholine (a glycerophospholipid) and sphingomyelin (a sphingolipid) are clear when their spacefilling 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 spacefilling 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. Sphingosine Ceramide Proliferation Growth arrest Apoptosis IMPORTANT ALSO FOR SKIN STRUCTURE AND FUNCTION QuickTime™ and a Sorenson Video decompressor are needed to see this picture. Necrosis: a pathological response to 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 out Cell contents are packaged in membrane bounded bodies, internal organelles still functioning, to be engulfed by neighbours. General inflammatory response is triggered Epitopes appear on plasma membrane marking cell as a phagocytic target. No spillage, no inflammation www.chembio.uoguelph.ca QuickTime™ e un decompressore TIFF (Non compresso) sono necessari per visualizzare quest'immagine. 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 esterified For storage or transport detergents in the intestine Glycerophoepholipid that act as intracellular messengers Eicosanoids Carry Messages to Nearby Cells Arachidonic acid 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 isoprenecontaining molecules • Isoprenoids are precursors for several important biomolecules Vitamin D production Vitamin A1 and its precursor and derivatives