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s2m1 biochem - membrane lipids & cholesterol
Ross University
18
Chemistry
Graduate
01/27/2010

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Term

what do all membrane lipids contain?

which lipids do all body tissues synthesize? with which exception?

where are the enzymes for synthesis of these lipids?

Definition

they all contain fatty acids

phosphoglycerides & sphingolipids

except RBC don't synthesize lipids

the enzymes are found in the cytosol & on the membrane

Term
what's the typical composition of a phospholipid?
Definition
fatty acid tail + head group
Term

what's the precursor to phospholipids?

where does the energy come from for the synthesis?

Definition

precursor - DHAP (dihydroxy acetone phosphate)

energy - from cytidine triphosphate

(instead of adenosine triphosphate, ATP)

Term

what can be used to make phosphatidylcholine?

what is needed to convert it?

Definition

phosphatidylserine

PL D enzyme & SAM

Term
what's the only antigenic phospholipid?
Definition
cardiolipin
Term

where is dipalmitoylphosphatidylcholine (DPPC) found?

what makes it & secretes it?

what disease is associated with it?

so how can we test for this disease?

how do we know if it's not present?

Definition

it's a component of lung surfactant

made by pneumocytes

respiratory distress syndrome - no surfactant in infant

test for it by measuring the DPPC to S(sphingomyelin) ratio

A ratio of 2 or above means maturity

 

Term

where is phospholipase C used?

what is the function of the products?

Definition

in second messenger pathway

it cuts IP2 into:

DAG -> (protein kinase C)

IP3 -> (Ca2+ release)

Term

1. what is phospholipase A2 used for?

2. what's the function of the products?

3. what's A2's second use?

4. what then fixes the problem?

5. what is A2 inhibited by?

6. where is alot of A2 found?

Definition

1. it releases arachadonic acid for thromboxane & 2. prostaglandin synthesis

3. repair mechanism for distorted lipids in membranes (cuts out the bad ones)

4. Acyltransferase adds new FA

5. glucocorticoids inhibit it

6. pancreatic excretions are rich in 'em

Term

what makes platelet activating factor water soluble?

what is it and what does it stimulate?

what effect does this have?

what effect does it have on neutrophils?

Definition

an acetyl group attached to it

it's a hormone that binds to platelet receptors

it causes their aggregation resulting in thrombotic & inflammatory events

causes neutrophils etc. to make superoxide radicals

Term

where are phosphatidylethanolamine & phosphatidylcholine found mostly?

what category do they fall under?

what disease are these associated with?

Definition

ethanolamine - nerve tissue

choline - heart muscle

they are both plasmalogens

associated with Alzheimer's disease

Term
what two compounds are the complex lipids synthesized from?
Definition
serine & palmitate
Term

what are gangliosides ?

where are some of them found?

what else do they determine?

Definition

complex sphingolipids with large polar head groups 

6% in grey matter of brain

determine blood groups

Term

what determines the different blood groups?

which enzyme determines A / B groups?

Definition

the sugar that's attached to a ganglioside.

A - N-acetylgalactosamine transferase

B - Galactose transferase

Term

Tay-Sachs disease

enzyme deficient? 

accumulating substance?

symptoms?

Definition

Hexoaminidase A

GM2 ganglioside

mental retard

blind

muscle weakness / seizures

Term

Gaucher disease

enzyme deficiency?

accumulating substance?

symptoms?

Definition

Glucocerebrosidase

Glucocerebroside

hapatosplenomegaly

mental retardation

osteoperosis of long bones

 

Term

Fabry disease

what's unique about this disease?

enzyme deficiency?

accumulating substance?

symptoms?

Definition

the only x-linked disease

α-galactosidase

Globosides

kidney / heart failure

red-purple skin rashes

burning pain in lower extremeties

Term

Krabbes disease

enzyme deficiency?

accumulating substance?

symptoms?

Definition

B-galactosidase

galacto-cerebroside

mental/motor deterioration

blind/deaf

loss of myelin in white matter of brain

Term
how do you test for disorders of sphingolipid metabolism?
Definition

extract lisosomal enzymes (specific for what disease you're testing for)

then add the compound they are supposed to break up.

if only half of it gets broken up, the person is a heterozygote for the disease etc.

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