Membrane Lipids

Question 1

Glycerophospholipids

• based off of what molecule
• functions of two important ones
• other functions

Answer 1

Both based off of phosphatidic acid
Lecithin (lung surfactant=reduces surface tension preventing collapse) and PI (cell signaling)

Membrane related , anchor proteins in membranes, bile component (mild detergent), lipoprotein component,

Question 2

Lecithin synthesis

Answer 2

de novo synthesis isn’t enough-essential dietary nutrient

Question 3

RDS aka….

• effects who
• reason
• how test?

Answer 3

Hyaline membrane disease

Premature infants/people with pneumocyte damage
PLs have not reached adequate levels
Can test in amniotic fluid
-Lecithn Sphingomyelin (L/S ratio)
---L/S ratio of 2 or more=maturity
---Less than 1.5=high risk for RDS

Question 4

Glycolipids

• 2 main
• contain?
• dervitive of?
• essential for? where most found?
• located where?
• Function

Answer 4

• Sulfatide(brain, nerve tissue, kidney) and gangliosides-from globoside (ganglion cells of CNS)
• Contains carbs and lipids
• derivitive of ceramides-long chain FA attached to sphingosine
• Essential for all membranes-greatest amount in nerve tissue
• Outer leaflet of PM
• Cell interactions, growth, dev

Question 5

glycosphingolipid synthesis

Answer 5

Similar to O linked glycoprotein synthesis

Syn in golgi

Use glycosyltransferases
Sequential addition of glycosyl monomers from UDP-sugar donors to acceptor

Question 6

GLycosphingolipid degredation

Answer 6

Lysosomes, acid hydrolyses, sequtioal removal last on, first off

sphingolipidosis

Dramatic neural tissue effects

Question 7

Tay-Sachs

• Dx
• Def
• Lipid accumulating
• Clinical Sx
• trx

Answer 7

Beta Hexosaminidase A

Assay for def enzyme

Azkanazi Jew

Ganglioside (found predom in nervous sys)

Cherry red macula, MR, blindness, muscular weakness, seizures, loss of vision, poor growth, ataxia

Supportive care till death

Question 8

Fabry’s

• DX
• Def
• Lipid accumulating
• Clinical Sx
• Trx

Answer 8

alpha galactosidase… X LINKED RECESSIVE (i think only one)

Clinical presentation and alpha-galactosidase activity

Globotriaosylceramide/Ceramide trihexoside

Skin rash, kidney failure (full Sx only in males), rosens over time, corneal clouding, renal failure and proteinuria, painless papule o skin, fatigue

ERT

Question 9

Metachonatic Leukodystrophy

• Def
• Lipid accumulating
• Clinical Sx

Answer 9

arylsulfase A

3-Sulfogalactosylceramide

MR, psychologic disturbances in adults, demyelination

Question 10

Krabbe’s

• Dx
• Def
• Lipid accumulating
• Clinical Sx
• Trx

Answer 10

Beta-galatocsidase

Clinical presentation, brain imaging, DNA testing

Galactosylceramide

Globoid (multinucleated macrophage in intracranial tissue), MR, myelin almost absent, gross neurological defects, developmental delays and regressions

Stem cell replacement if caught early or supportive care until death (adult onset progresses slower)

Question 11

Gaucher’s

• Def
• Lipid accumulating
• Clinical Sx

Answer 11

beta glucosidase

glucosylceramide

hepatosplenomegaly, long bone erosion, MR in infants

Question 12

Neumann-Pick

• Dx
• Def
• Lipid accumulating
• Clinical Sx
• Trx

Answer 12

Sphingomylinase

Dx-DNA testing/clnical presentation

Ashkenazi Jew

Sphingomyelin

Normal following birth, regression of previous acquired skillsCherry Red Macula, Hepatosplenomegaly (not in Tay Sachs), MR, Fatal in early life, anthems, low platelets

Supportive care until death

Question 13

Farber’s disease

• Def
• Lipid accumulating
• Clinical Sx

Answer 13

Ceramidase

Ceramide

Hoarseness, dermatitis, skeletal deformation, MR, fatal in early life