Term
| What are the neutral glycerolipids? |
|
Definition
1) monoacylglycerol
2) diacylglycerol
3) triacylglycerol |
|
|
Term
| What are some of the membrane lipids? |
|
Definition
-phospholipids
-glycolipids(no phosphate group)
-cholesterol |
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|
Term
| What are the types of phospholipids and what differentiates the two? |
|
Definition
1) Glycerophospholipids-backbone of glycerol-3phosphate
2) Sphingolipids-backbone of sphingosine |
|
|
Term
| What are the 3 roles of phospholipids? |
|
Definition
1) structural components of the membranes
2) receptors for small molecules
3) participate in signal transduction (esp- PI (phosphatidylinositol) derivatives |
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Term
| All phospholipids except for sphingomyelin are derived from? |
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Definition
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Term
| When you addy any fatty acids to C1 and C2 of glycerol-3-phosphate, what is produced? |
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Definition
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|
Term
| What type of fatty acid is typically added to position 1 and position 2 in phosphatidic acid? |
|
Definition
1-saturated fatty acid
2-unsaturated fatty acid |
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|
Term
| Sphingolipids are are based on a backbone of? |
|
Definition
| sphingosine- made from palmitic acid and serine |
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|
Term
| All sphingolipids are built on? |
|
Definition
|
|
Term
|
Definition
| sphingosine plus an acyl group added to the serine nitrogen |
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|
Term
| Sphingomyelin has an addition of what? |
|
Definition
| phosphoorylcholine group to produce the only sphingosine based phospholipid |
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|
Term
| What do you call the addition of one carbohydrate to ceramide? |
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Definition
| Cerebroside (also can be called a glycosphingolipid) |
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|
Term
| What do you call a cerebroside which contains more sugars, including sialic? |
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Definition
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|
Term
| If a ganglioside is mising the sialic acid, what is is called? |
|
Definition
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|
Term
| What contains an alcohol attached by a phosphodiester linkage to either diacylglycerol or sphingosine? |
|
Definition
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|
Term
| Only one phospholipid uses the sphingosine base, what is it called? |
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Definition
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Term
| A phospholipid containing an alcohol attached by a phosphodiester linkage to diacylglycerol is called? |
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Definition
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|
Term
| What are some of the head groups added to the phosphate of a phospholipid? |
|
Definition
1) glycerol
2) serine
3) inositol
4) phosphatidylglyercol
4) choline
5) ethanolamine |
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|
Term
| What do you call it when lipids are connected by ester bonds in a phospholipid? |
|
Definition
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|
Term
| What do you call it when one of the acyl groups is attached by an ether linkage? |
|
Definition
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|
Term
| What do you call it when one of the acyl chains is attached via a vinyl ether linkage? |
|
Definition
| alkenyl-type lipid (plasmalogen) |
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|
Term
| What do you call it when you have a loss of an acyl group from either position 1 or 2 of a phospholipid? |
|
Definition
|
|
Term
| Most of our phospholipids are of what type? |
|
Definition
|
|
Term
| What adds an acyl group to a glycerol backbone? |
|
Definition
|
|
Term
| What enzyme makes glycerol-3-phosphate from glycerol? |
|
Definition
| Glycerol kinase (uses ATP) |
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|
Term
| What enzyme makes Glycerol-3-phosphate from DHAP? |
|
Definition
| Glycerol-3-Phosphate DH (Uses NADH) |
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Term
| What is different between liver and all other tissues when it comes to making phospholipids? |
|
Definition
| Only liver can use glycerol |
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Term
| What is a biological signal, released from cells under appropriate conditions (ether lipid); leads to platelet aggregation, blood vessel dilation, and bronchoconstriction? |
|
Definition
| Platelet activating factor |
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|
Term
| What are the only plasmalogens found in human? |
|
Definition
1) choline plasmalogen
2) ethanolamine plasmalogen
3) serine plasmalogen |
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|
Term
| Where are the plasmalogens found? What is their function? |
|
Definition
| mitochondria membrane; function unknown |
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|
Term
| The key for ether lipid synthesis is? |
|
Definition
| An exchange of a fatty alcohol for an ester linkage |
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|
Term
| What is a fatal disease where the liver and brain mitochondria are depleted of plasmalogens? |
|
Definition
|
|
Term
| What happens in Zellweger Syndrome? |
|
Definition
1) Inability to transport peroxisomal enzymes into the peroxisomes
2) Initial steps of plasmalogen synthesis occurs in the peroxisomes
3) More of a disease of peroxisome biosynthesis than plasmalogen synthesis |
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|
Term
| B6 is required for sphingosine synthesis because of what reaction? |
|
Definition
| amino acid decarboxylation |
|
|
Term
| What are the precursors for sphingosine synthesis? |
|
Definition
|
|
Term
| The amide in ceramide is derived from? |
|
Definition
| An acyl CoA and the nitrogen from sphingosine |
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|
Term
| Sphingomyelin is derived from? |
|
Definition
| Ceramide plus a phosphocholine |
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|
Term
| The phosphocholine can come from either? |
|
Definition
1) PC-Phosphatidylcholine (donation of choline, found more often in the brain)
2) CDP choline (head group activation rxn) |
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|
Term
| What produces phospho-choline and ceramide from sphingomyelin? |
|
Definition
| Sphingomyelinase- lack of this results in Niemann-Pick disease |
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|
Term
| What can only work on ceramide and it would take a Sphingomyelin and make sphingosine and a fatty acid? |
|
Definition
| Ceramidase-lack of this enzyme results in Farber's disease |
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|
Term
| Glycerophospholipid Degradation: What results when Phospholipase A1 cleaves? |
|
Definition
| produces free fatty acid an 1-lysophospholipid |
|
|
Term
| Glycerophospholipid Degradation: What results when Phospholipase A2 cleaves? |
|
Definition
| Produces free fatty acid and 2-lysophospholipid |
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|
Term
| Glycerophospholipid Degradation: What results when Phospholipase C cleaves? |
|
Definition
| DAG and phosphorylated head group |
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|
Term
| Glycerophospholipid Degradation: What results when Phospholipase D cleaves? |
|
Definition
| Produces are a free head group and phosphatidic acid |
|
|
Term
| What Phospholipase has a cominined activity of A1 and A2? |
|
Definition
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|
Term
| What are the ganglioside functions? |
|
Definition
1) primarily found in the nervous system
2) receptors (bacterial toxins)
3) antigenic specificity
4) Hypothesized functions
-a-important for intracellular communication and signal transduction
-b-modulators of membrane enzyme activities
-c-ganglioside composition of cells altered when they becomes transferred(cancer;significance unknown) |
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|
Term
| The biosynthesis of gangliosides is similar to? |
|
Definition
| O-linked oligosaccharides |
|
|
Term
Biosynthesis of GM1
What are the important enzymes? |
|
Definition
1) Acyl-transferase (makes ceramide from sphingosine)
2) Glucosyl-transferase-adds Glucose to Ceramide
3) Galactosyl-transferase-adds Galactose to growing chain
-each step catalyzed by a different enzyme
-at least four distinct spingosine acyltransferases, each differing in fatty acid chain length specificity |
|
|
Term
| What is so important about glycosphingolipid degradation? |
|
Definition
| -Defects in degradation lead to disease due to accumulation of intermediates with the lysosomes and other cellular structures |
|
|
Term
| What are the basic principles of glycosphingolipid degradation? |
|
Definition
-There is a step wise removal of sugars from the glycosphingolipids(different enzyme for each step)
-Defect in enzyme leads to accumulation of substrate within lysosome, loss of lysosome function and disease |
|
|
Term
| What is the general name for glycosphingolipid degradation disorders? |
|
Definition
|
|
Term
| What are the symptoms for Tay-Sachs disease? |
|
Definition
It is an autosomal recessive disorder and will be fatal, but
also have these symptoms before death...
1) mental retardation and blindness
2) muscular weakness and seizures |
|
|
Term
| How type of genetic diseases are the sphingolipidoses? |
|
Definition
| All are recessive disorders except for Fabry's disease which is x-linked |
|
|
Term
| Does the rate of synthesis of the sphingolipids change when you have a disorder in the degradative pathway? |
|
Definition
| No, remains unchanged so you will have a continual accumulation of the intermediate product lead to lysosomal loss of function and disease |
|
|
Term
| Which pathways have a lysosomal disease associated with it? |
|
Definition
1) Glycogen metabolism
2) Protein synthesis/sorting
3) Sphingolipid Degradation |
|
|
Term
| In a person with Tay-Sachs, what accumulates? |
|
Definition
GM2- levels up to 300 times normal
GA2- levels up to 20 times normal |
|
|
Term
| GM2 is different from GA2 because? |
|
Definition
| GA2 lacks NANA- it is the asiaolo- derivative of GM2 |
|
|
Term
| Hexosaminidase removes what from glycosphingolipids? |
|
Definition
|
|
Term
| How many different subunits in Hexosaminidase A? |
|
Definition
-two subunits, a and ß, which are encoded by different genes (Hex A and Hex B, respectively)
-The number of a chains in the complex is unknown, so the molecule is represented as anß2 |
|
|
Term
|
Definition
|
|
Term
| Where is globoside found? |
|
Definition
|
|
Term
| What are the biochemical properties of HexB? |
|
Definition
| -it is a ß4 tetramer, encoded by the Hex B gene |
|
|
Term
|
Definition
| It removes N-acetylgalactosamine from GA2 and globoside (Hex A is required fro GM2) |
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|
Term
| If a patient has Tay-Sachs symptoms, but in a test tube both Hex A and Hex B are active, what is wrong? |
|
Definition
-Sandhoff's Activator Disease
-It was discovered that Hex A (but not Hex B) requires an activator protein for maximal activity. The newly diagnosed patients were missing the activator, and therefore were having trouble degrading GM2. This led to the Tay-Sachs like symptoms |
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|
Term
| What is synthesized from CDP-DAG and Inositol? |
|
Definition
|
|
Term
| Where is Phosphatidyl-Inositol found? |
|
Definition
| In the inner leaflet of plasma membranes; the outer leaflet of cytoplasmic organelles(ie- it is always facing the cytoplasm) |
|
|
Term
|
Definition
PI-> PIP-> PIP2-> inositol-phosphate->IP3(inositol-triphosphate)-> DAG
then repeat this continual cycle |
|
|
Term
| The cycling of PI intermediates is important in? |
|
Definition
1) Histamine secretion by mast cells
2) serotonin release by blood platelets
3) aggregation of blood platelets
4) insulin secretion by pancreatic islet cells
5) epinephrine secretion by adrenal chromaffin cells
6) smooth muscle contraction
7) visual signal transduction by invertebrate photo receptors |
|
|
Term
| What are the second messengers from the PI cycle? |
|
Definition
|
|
Term
| Tell me about the second messenger generation with PIP2? |
|
Definition
1) agonist binds to a receptor
2) PIP2 is broken down to DAG and IP3
3) DAG activates Protein kinase C
4) IP3 activates calcium mobilization
5) cellular response occurs |
|
|
Term
| IP3 induces the release of calcium from? |
|
Definition
|
|
Term
| What can interupt the PI cycle? What happens? |
|
Definition
| Lithium- second messengers can't be generated at the sam rate |
|
|
Term
What does this?
1) Activates, with phosphatidylserine, protein kinase C
2) Phosphorylation required for the response, but specific substrates difficult to identify |
|
Definition
|
|
Term
What is this?
1) PI, at the two position has large levels of this C20:4 fatty acid
2) It is released by phospholipase A2
3) Leads to increases in thromboxane and prostaglandin production |
|
Definition
|
|
Term
What is this?
1) Releases calcium ions from the intracellular stores(ER)
2) calcium binds to calmodulin, regulates activity of enzyme via this subunit |
|
Definition
|
|
Term
|
Definition
| AId in tumor growth by binding and activating protein kinase C |
|
|
Term
|
Definition
| Inhibits prostaglandin production by forming a covalent bond with cyclo-oxygenase |
|
|
Term
| What does Platelet activating factor do? |
|
Definition
-It's release results in platelet aggregation
-Affects muscle, brain, liver and kidney as well |
|
|
Term
| What is a misture of proteins and lipids required for lung elasticity? |
|
Definition
| Lung surfactant- lack of results in respiratory distress syndrome in newborns caused by a lack of surfactant |
|
|
Term
| What is the major lipid in lung surfactant? |
|
Definition
| dipalmitoylphosphatidylcholine |
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