complex lipid metabolism

Question 1

where are most phospholipids synthesized

Answer 1

smooth ER (distributed by exocytosis)

Question 2

what are the predominant lipids of cell membranes

Answer 2

phospholipids

Question 3

what are the two types of phospholipids

Answer 3

glycerolphospholipids

spingophospholipids

Question 4

what are the three characteristics of phosphatidic acid

Answer 4

glycerol backbone
2 fatty acyl groups
phosphate group

Question 5

what are the 4 characteristics of sphingophospholipids

Answer 5

sphingosine backbone
long-chain FA at carboxyl group
long chain desaturated group
phosphate group

Question 6

what is the structure of a plasmalogen?

Answer 6

a phosphatidic acid w/ an unsaturated alkyl group at carbon 1

Question 7

what is the significant plasmalogen in nerve tissue?

Answer 7

phosphatidalethanolamine

Question 8

what is the significant plasmalogen in heart muscle?

Answer 8

phosphatidalcholine

Question 9

what is the purpose of PAF (platelet-activating factor)

Answer 9

it triggers potent thrombotic and acute inflammatory events

Question 10

where is cardiolipin found in eukaryotes?

Answer 10

virtually exclusive to the inner mitochondrial membrane

Question 11

what are three important functions of sphingomyelin?

Answer 11

precursor of glycolipids
only significant sphingophospholipid in humans
important for myelin nerve fibers

Question 12

what are the 2 things needed to synthesize phosphatidic acid?

Answer 12

glycerol phosphate

two fatty acyl CoA

Question 13

what part of the body cannot synthesize phosphatidic acid?

Answer 13

RBCs

Question 14

what are the primary sources of choline and ethanolamine?

Answer 14

diet

phospholipid turnover

Question 15

phosphatidylcholine is secreted as what from the liver?

Answer 15

a component of serum lipoproteins

bile

Question 16

what is the major lipid component of lung surfactant?

Answer 16

DPPC

Question 17

what ratio can be used to test fetal lung maturity?

Answer 17

DPPC: sphingomyelin ratio

Question 18

Phosphatidylinositol is unusual in structure because why?

Answer 18

steric acid on carbon 1

arachidonic acid on carbon 2

Question 19

what coenzyme is required for the synthesis of sphingomyelin?

Answer 19

derivative of vitamin B6

Question 20

what is the deficient enzyme in Niemann-Pick disease?

Answer 20

sphingomyelinase

Question 21

what are the two types of Niemann-Pick disease and which is more severe?

Answer 21

Type A and B

A is more severe

Question 22

what is in the structure of a glycolipid?

Answer 22

carbohydrate + lipid components

derivative of ceramide

Question 23

where are glycolipids found?

Answer 23

outer leaflet of the PM

Question 24

genetic disorders associated w/ an inability to degrade glycolipids results in what type of disease?

Answer 24

lysosomal storage

Question 25

what are sphingolipidoses?

Answer 25

lysosomal storage diseases caused by the deficiency of lysosomal hydrolases for glycolipids

Question 26

how are sphingolipidoses diagnosed?

Answer 26

measuring enzyme activity in cultured fibroblasts or peripheral leukocytes
DNA analysis
histological exam of tissue

Question 27

most lysosomal storage diseases are caused by a deficiency in the degradation of what?

Answer 27

GM2 gangliosides

Question 28

what is the enzyme defective in Tay Sachs

Answer 28

hexosaminidase A

Question 29

what is the accumulated product in Tay Sachs

Answer 29

GM2 gangliosides

Question 30

what enzyme is defective in Gaucher disease?

Answer 30

cocerebrosidase enzyme

Question 31

what accumulates in Gaucher disease?

Answer 31

glucocerebroside in phagocytic cells and CNS

Question 32

what are three clinical subtypes of Gaucher disease?

Answer 32

type 1 non-neuronopathic form
type II acute neuronopathic form (severe)
type III intermediate