Triglycerides, Phospholipids, Sphingolipids

Front 1

What is triglycerol?

Back 1

Glycerol attached to 3 FA

Front 2

What is phosphatidic acid?

Back 2

Glycerol backbone with FA chain on sn1 and sn2 and PO4 group on sn3

Front 3

How do you form diacylglycerol?

Back 3

cleave PO4 group off of phosphatidic acid ith PAP (phosp. acid phosphatase)

Front 4

How do you form triacylglycerol?

Back 4

-use an acyl transferase to add 3rd FA to diacylglycerol
-acyl transferase used = DGAT

Front 5

What is DGAT?

Back 5

The acyl transferase used to form triacylglycerol from diacylglycerol. It is regulated and .: control triacyglycerol synthesis.

Front 6

What is MGAT?

Back 6

-Monoacylglycerol acyl transferae
-used to convert monoacyl glycerols to diacyl glycerols

Front 7

How can glycolysis affect triglycerides?

Back 7

Byproducts of glycolysis can be turned into FA by adding acyl groups thru the efforts of MGAT and DGAT

Front 8

Where is fat stored?

Back 8

Adipose tissue

Front 9

Why do we store fat?

Back 9

Insulation, useful during food shortage, protection for organs

Front 10

How is FA mobilized/liberated?

Back 10

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

Front 11

What are phospholipids?

Back 11

Glycerol backbone wiht FA in sn1 and sn2 positiokns, and a PO4 gp and head gp at the sn3 position

Front 12

What is phosphatidic acid?

Back 12

a diacylglycerol with a phosphate gp

Front 13

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)

Back 13

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

Front 14

What are the 5 ways to synthesize phospholipids?

Back 14

1)Kennedy path
2) Alternate Path
3)Exchange
4)Decarboxylation
5)Methylation

Front 15

What is produced in the Kennedy path?

Back 15

PC and PE

Front 16

What E source is used to fuel this path?

Back 16

CTP (follow the CDP to distinguish between Kennedy path and the alternate path)

Front 17

What are the steps involved in teh Kennedy path?

Back 17

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)

Front 18

What is the alternate path?

Back 18

Used to generate PI and PG
=> CDP goes onto DAG and not the choline or ethanolamine
=> enz used= CT

Front 19

Difference between Kennedy path and Alternate path?

Back 19

Kennedy path: CDP attached to the ethanolamine/choline
Alternate Path: CDP attaches to the DAG

Front 20

What is the Exchange reaction?

Back 20

Generate PS (from PE)
PE + serine=> PS + ethanolamine
-Transferase catalyzes this reaction

Front 21

What is the Decarboxylation reaction?

Back 21

PS=> PE + CO2
Enzyme= PSD

Front 22

To interconvert btw PS and PE:

Back 22

To make PE, need a decarbox., using PSD
To make PS, need to exchange and use transferase

Front 23

What is methylation?

Back 23

Make PC from PE
(PC has 3 more CH3 gps on it)
Need a methyl transferase: PEMT, takes the methyls from SAM

Front 24

What are the 6 common phospholipids?

Back 24

PA, PE,PC, PG, PI, PS

Front 25

Cardiolipin?

Back 25

-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

Front 26

Why are phospholipids so good at making membranes?

Back 26

Phospholipids are amphipathic (can be hydrophobic or hydrophilic)

Front 27

What is Flip-flop?

Back 27

-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

Front 28

What is a phospholipase?

Back 28

Enz that degrades phospholipids

Front 29

Where do the following phospholipases cleave?
a) phospholipase A1
b)phospholipase A2
c)Phospholipase C
d) Phospholipase d

Back 29

a) at the sn1
b)at the sn2
c)on the left side of the PO4
d)on the right side of the PO4

Front 30

What are the products of oxidation of arachidonic acid?

Back 30

-Leukotrienes
-Prostaglandins
-Thromboxanes

Front 31

How doesaspirin affect the oxidation of arachidonic acid?

Back 31

Aspirin inhibits the conversioln of arachidonic acid to prostaglandins or thromboxanes

Front 32

What do sphingolipids look like?

Back 32

DAG

Front 33

5 examples of sphingolipids?

Back 33

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)

Front 34

Differnces btw glycerolipid and sphingolipid?

Back 34

1) at sn1:Glycero-> ester bond, sphingo ->db
2) at sn2: Glycero-> ester bond, sphingo-> amide bond

Front 35

How do you get sphingolipids?

Back 35

Serine + Palmitoyl CoA = ceramide

Front 36

Howdo you synthesize sphingomyelin?

Back 36

Ceramide + PC => Sphingomyelin + DAG
(Remember:sphingomyelin
looks like PC)
(Serine + Palmitoyl CoA => Ceramide)

Front 37

What are glycosphingolipids?

Back 37

sphingolipids with a sugar attached to the lipid portion

Front 38

What are the 3 group of Glycosphingolipids and their characteristics?

Back 38

-Cerebrosides: have a singlesugar attached to them
-Globosides: linearly linked sugars (2, 3 or 4)
--Gangliosides: have branched sugars that contain neuraminic acid

Front 39

Why do gangliosides need to be degraed?

Back 39

Otherwise you can get a nervous system disease

Front 40

What is the differnce between Sphingolipids, Plasmalogen and Platelet activating factor?

Back 40

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)