15: Complex Lipids Flashcards
Fatty acids are used in the synthesis of _____ for energy storage and phospholipids and ______ which are components of cell membranes.
Fatty acids are used in the synthesis of triacyl glycerols for energy storage and phospholipids and sphingolipids which are components of cell membranes.
________ are synthesized from glycerol 3-phosphate and fatty acyl CoA , via phosphatidic acid. Charged and uncharged polar head groups are then added to ________ to form the glycerophospholipid.
Glycero-phospholipids are synthesized from glycerol 3-phosphate and fatty acyl CoA , via phosphatidic acid. Charged and uncharged polar head groups are then added to phosphatidic acid to form the glycerophospholipid.
Sphingolipids are synthesized through sphingosine which is derived from _____ and ______.
Sphingolipids are synthesized through sphingosine which is derived from serine and palmitoyl CoA.
Sphingomyelin is the sole ________ phospholipid and is found in ______ and in high concentration in the myelin sheath.
Sphingomyelin is the sole sphingosine phospholipid and is found in cell membranes and in high concentration in the myelin sheath.
Glycolipids are sphingolipids with sugar components and include _______, _______, _______ and _______.
Glycolipids are sphingolipids with sugar components and include cerebrosides, globosides, gangliosides and sulfatides.
Phospholipids are degraded by specific _______.
Phospholipids are degraded by specific phospholipases.
Glyco-sphingolipids are degraded by a series of _______ enzymes. Lysosomal lipid storage
defects based on genetic defects in specific degradation enzymes are called _______. As ______ are enriched in brain membranes many of these hereditary sphingolipidoses lead to neurologic deterioration and early death.
Glyco-sphingolipids are degraded by a series of lysosomal enzymes. Lysosomal lipid storage
defects based on genetic defects in specific degradation enzymes are called Sphingolipidoses. As glycol-sphingolipids are enriched in brain membranes many of these hereditary sphingolipidoses lead to neurologic deterioration and early death.
See purple on pg. 310
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_________ are the predominant phospholipids in cell membranes. ______ acid is the simplest glycerophospholipid.
In glycerophospholipids the phosphate group of ________ acid is esterefied to a compound containing an alcohol which forms: ______, ______, & _______ are the 3 main glycerophospholipids in cell membranes.
Glycerophospholipids are the predominant phospholipids in cell membranes. Phosphatidic acid is the simplest glycerophospholipid.
In glycerophospholipids the phosphate group of phosphatidic acid is esterefied to a compound containing an alcohol which forms: Phosphatidylserine, phosphtidylethanolamine, & phosphatidylcholine are the 3 main glycerophospholipids in cell membranes.
Cardiolipin = 2 molecules of _______ acid esterefied through their phosphate. It is found in the membranes of _____ & eukaryotic ______ ______ membranes–supports complexes of e- transport chain.
Cardiolipin = 2 molecules of phosphatidic acid esterefied through their phosphate. It is found in the membranes of bacteria & eukaryotic inner mitochondrial membranes–supports complexes of e- transport chain.
Ether Glyceolipids:
Phosphatidal _______ is abundant in nerve tissue
_____ ______ ____ is an ether glycerolipid–stimulates thrombotic & acute inflammatory response.
The plasmalogen _________ is enriched in heart muscle
_____ _____ & _____ _____ are the 2 most abundant ether lipids in mammals.
Ether Glyceolipids:
Phosphatidal ethanolamine is abundant in nerve tissue
Platelet activating factor is an ether glycerolipid–stimulates thrombotic & acute inflammatory response.
The plasmalogen phosphatidalcholine is enriched in heart muscle
Phosphatidal serine & phosphatidal choline are the 2 most abundant ether lipids in mammals.
The backbone of sphingomyelin is sphingosine. A ______ is attatched to the amino group in sphingosine via an _____ bond, this is a ceramide. Carbon 1 of sphingosine becaomes esterefied to ______ _____ forming sphingomyeilin–found in the myelin sheath.
The backbone of sphingomyelin is sphingosine. A LCFA is attatched to the amino group in sphingosine via an amide bond, this is a ceramide. Carbon 1 of sphingosine becaomes esterefied to phophoryl choline forming sphingomyeilin–found in the myelin sheath.
Galactocerebrosides = uncharged glycosphingolipids with a ______ or _______–found in nerve tissue like myelin sheathe. The glycosphingolipids differs from sphinomyelin in not having a phosphate group. Instead a sugar is attached to ________ by an O-glycosidic bond. The sugar is the polar head group & the ______ = hydrophobic tail that is in the hydrophobic core of membranes.
Galactocerebrosides = uncharged glycosphingolipids with a galactose or glucose–found in nerve tissue like myelin sheathe. The glycosphingolipids differs from sphinomyelin in not having a phosphate group. Instead a sugar is attached to ceramide by an O-glycosidic bond. The sugar is the polar head group & the ceramide = hydrophobic tail that is in the hydrophobic core of membranes.
Sphingomyeilin and Phosphyl Choline are on _____ leaflet of the cell membrane.
Phosphoserine & phosphoinosital phosphoethanolamine are on _____ leaflet.
Lipid rafts contain ______, _______, & ______ rich domains called lipid rafts. They are involved in functions like assembly of signaling molecules, membrane protein trafficking, regulating neurotransmission, & receptor trafficking.
Phospholipids & sphingomyelin filliping vs their concentration gradient uses ATP-dependent ______. When they flip down their gradient, they require ______ or ______.
Sphingomyeilin and Phosphyl Choline are on outside leaflet of the cell membrane.
Phosphoserine & phosphoinosital phosphoethanolamine are on inside leaflet.
Lipid rafts contain cholesterol, sphingolipid, & glycolipid rich domains called lipid rafts. They are involved in functions like assembly of signaling molecules, membrane protein trafficking, regulating neurotransmission, & receptor trafficking.
Phospholipids & sphingomyelin filliping vs their concentration gradient uses ATP-dependent flippases. When they flip down their gradient, they require scramblases or floppases.
Try to describe the synthesis of glycerophospholipids & see pg. 321-322
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Describe surfactant & its role in respiratory distress syndrome
Dipalmitoylphosphatidylcholine, DPPC, is a Phosphatidylcholine with C1 & C2 esterified to palmitate. It is produced from type 2 pneumocytes & it is the major lipid component of surfactant which reduces the surface tensio (pressure needed to reinflate alveoli) n of the lungs preventing their colapse.
Deficiency in the synthesis of the components of surfactant leads to respiratory distress syndrome in preterm infants.
Know that ________ can become Ethanolamine plasmalogen.
Know that dyhydroxyacetone phosphate (DHAP) can become Ethanolamine plasmalogen.
The synthesis of all ________ begins with the formation of ceramide. Ceremide is made from the condensation of ______ + _______. Ceramide is the precursor of _________ & the other _________.
The synthesis of all sphingolipids begins with the formation of ceramide. Ceremide is made from the condensation of serine + palitoyl-CoA. Ceramide is the precursor of sphingomyelin & the other sphinolipids.
Try to describe the synthesis of sphingolipids & see pg. 327
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The degradation of glycerophospholipids is catalyzed by _______ found in all tissues & _______ juice. Phospholipases A1 & A2 cleave off fatty acids @ C1 & C2 leaving behind _______. Phospholipase C cleaves off the phosphorylated head group giving _______. Phospholipase D cleaves off the head group giving _______.
Phospholipases can aslo be used to remodel phosoholipids in _______. The removed chains can be replaced with new ones by ________. This is how surfactant component ______ is enriched in the lungs & how carbon 2 of PI is associated with ________ acid.
The degradation of glycerophospholipids is catalyzed by phospholipases found in all tissues & pancreatic juice. Phospholipases A1 & A2 cleave off fatty acids @ C1 & C2 leaving behind lysophospholipids. Phospholipase C cleaves off the phosphorylated head group giving DAG. Phospholipase D cleaves off the head group giving PA (phosohatidic acid).
Phospholipases can aslo be used to remodel phosoholipids in membranes. The removed chains can be replaced with new ones by fatty acyl CoA transferase. This is how surfactant component DPPC is enriched in the lungs & how carbon 2 of PI is associated with arachadonic acid.
Phosphatydylinisitol has a ______ acid @ C1 & ______ acid @ C2. PI serves as a resevoir for Arachadonic acid which can be released by phospholipase _____. The phosphorylation of PI creates ______.
Phosphatydylinisitol has a stearic acid @ C1 & arachadonic acid @ C2. PI serves as a resevoir for Arachadonic acid which can be released by phospholipase A2. The phosphorylation of PI creates PIP2.
Describe the basis for lysosomal storage diseases
- Glycosphingolipids are internalized by endocytosis. The endocytic vesicles fuse with lysosomes which contain the hydrolytic enzymes.
- Specific lysosomal enzymes cleave specific glycosidic bonds following the pattern of “last on first off”.
- Defects in cleavage lead to accumulation of the substrate in these lysosomal storage diseases.
- In normal cell homeostasis synthesis and degradation of glycosphingolipids are balanced.
- When a specific lysosomal hydrolase is deficient or defective a sphingolipid accumulates.
- Lysosomal storage diseases caused by defects or diminishment of these enzymes are called Sphingolipidoses.
- As Glycosphingolipids are enriched in nerve tissue many of these sphingolipidoses cause neurologic problems and premature death.
Disease: Tay Sachs
Defective enzyme:
Accumulated substrate:
Disease: Tay Sachs
Defective enzyme: deficiency of B-hexosaminidaseA & activator protein
Accumulated substrate: Gangliosides
Disease: Gaucher
Defective enzyme:
Accumulated substrate:
Disease: Gaucher
Defective enzyme: glucocerebrosidase
Accumulated substrate: Glucocerebrosides
Disease: Metachromatic leukodystrophy
Defective enzyme:
Accumulated substrate:
Disease: Metachromatic leukodystrophy
Defective enzyme: Arylsulfatase A deficiency & deficiency of activator protein
Accumulated substrate: sulfatides
Disease: Krabbe Disease
Defective enzyme:
Accumulated substrate:
Disease: Krabbe Disease
Defective enzyme: B-Galactosidase also known as galactocerebrosidase
Accumulated substrate: galactocerebrosides
Disease: GM1 Gangliosidosis
Defective enzyme:
Accumulated substrate:
Disease: GM1 Gangliosidosis
Defective enzyme: B-Galactosidase
Accumulated substrate: Ganglioside GM1 & Keratan sulfate
Disease: Sandhoff
Defective enzyme:
Accumulated substrate:
Disease: Sandhoff
Defective enzyme: B-hexosaminidaseA & B
Accumulated substrate: GM2 & Globosides
Disease: Fabry
Defective enzyme:
Accumulated substrate:
Disease: Fabry
Defective enzyme: a-Galactosidase
Accumulated substrate: Globosides
Disease: Nemann-Pick
Defective enzyme:
Accumulated substrate:
Disease: Nemann-Pick
Defective enzyme: sphingomyelinase
Accumulated substrate: sphingomyelin
Disease: Farber
Defective enzyme:
Accumulated substrate:
Disease: Farber
Defective enzyme: ceraminidase
Accumulated substrate: ceramide
Review all lysosomal storage diseases in figure on pg. 332
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