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40 Cards in this Set
- Front
- Back
What is triglycerol?
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Glycerol attached to 3 FA
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What is phosphatidic acid?
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Glycerol backbone with FA chain on sn1 and sn2 and PO4 group on sn3
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How do you form diacylglycerol?
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cleave PO4 group off of phosphatidic acid ith PAP (phosp. acid phosphatase)
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How do you form triacylglycerol?
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-use an acyl transferase to add 3rd FA to diacylglycerol
-acyl transferase used = DGAT |
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What is DGAT?
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The acyl transferase used to form triacylglycerol from diacylglycerol. It is regulated and .: control triacyglycerol synthesis.
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What is MGAT?
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-Monoacylglycerol acyl transferae
-used to convert monoacyl glycerols to diacyl glycerols |
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How can glycolysis affect triglycerides?
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Byproducts of glycolysis can be turned into FA by adding acyl groups thru the efforts of MGAT and DGAT
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Where is fat stored?
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Adipose tissue
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Why do we store fat?
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Insulation, useful during food shortage, protection for organs
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How is FA mobilized/liberated?
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1) Hormone (glucagon or epinephrin) binds and G-ptn is activated
2) G-ptn induced adenylyl cyclase activation and cAMP generation from ATP 3) cAMP binds and activates PKA 4) PKA phosphorylates and activates hormone sensitive lipase and phosphorylates perilipin, opening up holes on the lipid droplet surface 5)Hormone sensitive lipase sneaks in and interacts with triacylglycerol, liberating FA 6) These FA are transpored in the blood by albumin |
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What are phospholipids?
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Glycerol backbone wiht FA in sn1 and sn2 positiokns, and a PO4 gp and head gp at the sn3 position
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What is phosphatidic acid?
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a diacylglycerol with a phosphate gp
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What do the head groups of the following look like?
a) Phosphotidylthanolamine (PE) b)Phosphotidylcholine (PC) c)Phosphotidylserine (PS) d)Phosphotidylglycerol (PG) e)Phosphotidylinositol (PI) |
a) two CH2 grops with an NH3 on the end (CH2-CH2-NH3)
net charge=0 b) CH2-CH2-N(CH3)3 net charge=0 c)head gp with serine, neg charge on COO- .: net charge= -1 d)2 OH gps net charge= -1 e) has several OH gps that can all get phosphorylated net charge = -4 |
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What are the 5 ways to synthesize phospholipids?
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1)Kennedy path
2) Alternate Path 3)Exchange 4)Decarboxylation 5)Methylation |
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What is produced in the Kennedy path?
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PC and PE
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What E source is used to fuel this path?
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CTP (follow the CDP to distinguish between Kennedy path and the alternate path)
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What are the steps involved in teh Kennedy path?
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1)Start with Enthanolamine or choline and phosphorylate it using ATP
2)Cytidyltransferase (CT) adds CTP gp to phosphoethanolamine/choline . End up with CDP attached to the choline or ethanolamine which were added to the head group 3) Add diacylglcerol to the ethanoamine/choline and CMP falls of (.: left one PO4 to be the PO4 of phospholipid) |
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What is the alternate path?
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Used to generate PI and PG
=> CDP goes onto DAG and not the choline or ethanolamine => enz used= CT |
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Difference between Kennedy path and Alternate path?
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Kennedy path: CDP attached to the ethanolamine/choline
Alternate Path: CDP attaches to the DAG |
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What is the Exchange reaction?
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Generate PS (from PE)
PE + serine=> PS + ethanolamine -Transferase catalyzes this reaction |
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What is the Decarboxylation reaction?
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PS=> PE + CO2
Enzyme= PSD |
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To interconvert btw PS and PE:
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To make PE, need a decarbox., using PSD
To make PS, need to exchange and use transferase |
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What is methylation?
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Make PC from PE
(PC has 3 more CH3 gps on it) Need a methyl transferase: PEMT, takes the methyls from SAM |
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What are the 6 common phospholipids?
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PA, PE,PC, PG, PI, PS
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Cardiolipin?
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-Formed from 2 PG that share a glycerol head gp
-mostly present in the heart, but can also be found in the IMM of mito |
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Why are phospholipids so good at making membranes?
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Phospholipids are amphipathic (can be hydrophobic or hydrophilic)
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What is Flip-flop?
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-E unfavorable rxn.
-hydrophilic head must past through hydrophobic interior of bilayer -Regulated mech to control which phospholipids are exposed on the outer leaflet. -Mediated by enz Flippase |
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What is a phospholipase?
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Enz that degrades phospholipids
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Where do the following phospholipases cleave?
a) phospholipase A1 b)phospholipase A2 c)Phospholipase C d) Phospholipase d |
a) at the sn1
b)at the sn2 c)on the left side of the PO4 d)on the right side of the PO4 |
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What are the products of oxidation of arachidonic acid?
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-Leukotrienes
-Prostaglandins -Thromboxanes |
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How doesaspirin affect the oxidation of arachidonic acid?
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Aspirin inhibits the conversioln of arachidonic acid to prostaglandins or thromboxanes
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What do sphingolipids look like?
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DAG
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5 examples of sphingolipids?
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1-Ceramides (looks like DAG)
2-Sphingomyelin (looks like PC) 3-Glucosylcerebroside (1 sugar attached) 4-Globoside (2 sugars attached, not branched) 5-Ganglioside (branched sugars attached) |
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Differnces btw glycerolipid and sphingolipid?
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1) at sn1:Glycero-> ester bond, sphingo ->db
2) at sn2: Glycero-> ester bond, sphingo-> amide bond |
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How do you get sphingolipids?
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Serine + Palmitoyl CoA = ceramide
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Howdo you synthesize sphingomyelin?
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Ceramide + PC => Sphingomyelin + DAG
(Remember:sphingomyelin looks like PC) (Serine + Palmitoyl CoA => Ceramide) |
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What are glycosphingolipids?
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sphingolipids with a sugar attached to the lipid portion
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What are the 3 group of Glycosphingolipids and their characteristics?
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-Cerebrosides: have a singlesugar attached to them
-Globosides: linearly linked sugars (2, 3 or 4) --Gangliosides: have branched sugars that contain neuraminic acid |
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Why do gangliosides need to be degraed?
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Otherwise you can get a nervous system disease
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What is the differnce between Sphingolipids, Plasmalogen and Platelet activating factor?
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at sn1:
Sphingolipid: db (alkene) Plasmalogen: ether linked db (ehter linked too an alkene) Platelet act. fact.:ether linked sb (ether linked to an alkane) |