Membrane Lipids Flashcards Preview

Biochemistry MBS > Membrane Lipids > Flashcards

Flashcards in Membrane Lipids Deck (30):
1

lipids and cancer

-cancerous cells need to make a lot of membrane lipid in order to divide rapidly
-upregulate citratelyase and down regulate FA oxidation

2

sphingosine 1 phosphate

contributes to cancer and inflammation
-crohns, ulcerative colitis

3

lysosomal storage diseases

-can not break down sphingolipids due to genetic disorders of metabolism

4

different scaffolds

-glycerol
-sphingosine

5

glycerophospholipids

-2 FAs in ester linkages as positions 1 and 2
-head group in a phosphodiester linkage at position 3

6

head groups

-serine
-choline
-ethanolamine
-glycerol
-inositol

7

cardiolipin

-double phospholipid
-exclusive to the inner membrane of the mitochondria

8

what do fatt acid salts form

-micelles
-individual units are wedge shpaed with a carboxylic head and an aliphatic tail

9

phospholipids form

-membrane bilayers
-individual units are cylindrical
-glycerophospholipids will spontaneously form bilayers in awueous solution

10

flip flopping of membrane lipids

-very unlikely to happen spontaneously
-the enzyme flippase is required
-this has implications in membrane properties such as in RBC's (PC on outer and PE and PS on inner)

11

common lecithin

-1 stearoyl, 2 oleoyl-phosphatidyl choline
-most abundant human membrane lipid
-unsaturated FA on C2 lowers melting point creating a fluid membrane

12

lung sufractant

-1,2 palmytoil-phosphatidyl choline
-reduced fluidity important for coating air-water interface, preventing alveolar collapse
-deficiency can lead to respiratory distress syndrome in premature infants

13

what does the formation of glycerophospholipids start with?

PA or DAG

14

general mechanism for head group addition

1. CDP activation of one hydroxyl by adding phosphate via kinase then CTP via cytidyltransferase
2. second hydroxyl displaces CMP to give phosphodiester

15

starting reactants to make ethanolamine or choline

-start with a head group activated with CDP then add diacylglycerol

16

starting reactants for making inositol (PI), glycerol, or PGC3 (cardiolipin)

-start with diacylglycerol activated with CDP then add a head group

17

glycerophospholipid interconversion

-SAM (S-adenosyl methionine) is used as a methyl donor in several processes
-only way to form PS is to convert it from PE

18

plasmalogens

-glycerophospholipids with fatty alcohol in ether linkage at C1
-activated platelet secretion and alters membrane permeability
-abundant plasmalogens in mitochondrial inner membrane may resist oxidative damage that would hydrolyze the ester bonds in normal PL's

19

phospholipases

-PLA2 release PUFAs acted upon by oxygenases to make intracellular signaling molecules
-PLAs rearrange FA's
-PLA's are found in many venoms

20

modified FA's as intracellular signals

-certain stresses induce phospholipase A to release long chin PUFAs from membrane phopholipids
-eicosanoids

21

cyclooxygenase
(phospholipase)

-gives rise to prostaglandins and thromboxanes which act as short range intracellular signals
-removes 2 double bonds, subscript shows number remaining

22

lipoxygenases (phospholipase)

-generate leukotrienes
-important for the immune response
-number of double bonds is unchanged
-modulate cellular chemotaxis, cytokine release
-mediate vascular permeability and bronchioconstriction

23

DAG

-second messenger
-activates PKC

24

IP3

-causes release of Ca2+
-activates calmodulin kinase
-promotes growth and development

25

what are DAG and IP3 released from

-PIP
-extracellular signal binds membrane spanning receptor to activate PLC which cleaves PIP into IP3 and DAG

26

sphingolipids

-membrane lipids not based on glycerol
-based on sphingosine
-common membrane component in myelin sheath, sphingolyelin with C24 FA's provides electrical insulation

27

multiple myeloma

-auto immune disease where you lose myelination in the CNS

28

types of glycolipid, what is theur classification

-sulfatides
-globosides
-gangliosides (charged, neuraminic acid)
-these are a type of sphingolipid
-glucose added as UDP glucose or UDP galactose

29

blood grouping antigens

-these are gangliosides and globosides
-they are markers in cellular recognition

30

normal sphingolipid breakdown pathways

-membrane lipids are constantly pulled from the surface into endosomes
-some are reused others are broken down in lysosomes and their components recylcled
-each sugar linkage in the glycosphingolipids (cerebrosides, globosides, and gangliosides) requires a seperate enzyems for removal