Blomquist: Lipids part II Flashcards
What three things make up phospholipids?
- glycerol
- fatty acids
- bases
What are some common bases that make up phospholipids?
ethanolamine
choline
serine
glycerol
What is the most abundant phospholipid?
phosphatidylcholine
Double bonds in fatty acids make membranes more (blank); cholesterol makes membranes less (blank)
fluid; fluid
(blank) are structures outside of the cell membrane facing the extracellular fluid.
glycolipids
Components of cell membranes
cholesterol, integral proteins, peripheral proteins, glycoproteins, carbohydrate, glycolipids
Phospholipid comprised of two phosphatidic acids joined by a glycerol
Comprises about 20% of the inner mitochondria membrane
Abundant in bacteria
cardiolipin
Phospholipid with an ether linkage
plasmalogen
Mediates hypersensitivity, allergic responses, others. Inactivated by hydrolysis of acetyl group and reacylation with fatty acyl group to form ether-type membrane phospholipid. First phospholipid shown to have special function.
Platelet activating factor
What group is at the R2 position of platelet activating factor?
acetyl group
A type of phospholipid that is rapidly turned over and is a part of a second messenger signal cascade
phosphoinositol (IP3)
oxytocin
vasopressin
histamine
angiotensin II
Hormones that use the IP3 pathway
Discuss the IP3 pathway in an example with activation by vasopressin.
Vasopressin binds to GPCR, takes GDP to GTP, GTP activates phospholipase C which cleaves PIP2 into IP3 and DAG. IP3 causes the release of calcium ions, and DAG activates PKC
When PKC is activated, it can stay active for a long time. However, Ca+ and DAG do not. What happens to each?
Ca+ will be pumped out of the cytoplasm (either into SR or out of cell) and DAG will turn back into a phospholipid
What cleaves PIP2 to IP3 and DAG?
Phospholipase C
Steps in phospholipid biosynthesis. What does it start with? What does it end with? Name an intermediate
Glycerol 3-phosphate Lysophosphatidic acid Phosphatidic acid DAG TAG
One route to forming phospholipids involves activation of a head group or base to a (blank). What does this require? Give an example.
CDP-base (cytidine diphosphate)
CTP
choline –> CDP choline
So, one way to generate phospholipids is to use a cytosine-nucleotide derivative, a CDP-[base], to donate a polar head group via a phospho[base] transferase. Give an example.
DAG —> phosphocholine transferase –> phosphatidylcholine
If you start with phosphatidylethanolamine, S-adenosylmethionine can donate a methyl group to form what major membrane lipid?
phosphatidylcholine
Phosphatidylserine can be formed by exchanging an (blank) for a serine
ethanolamine
Phosphatidylserine can be decarboxylation to form (blank)
phosphatidylethanolamine
A second way to synthesize phospholipids, such as PI and PS, is to activate (blank) with a cytosine-nucleotide lipid derivative, and form (blank).
DAG; CDP-DAG
(blank) can be added to CDP-DAG to form phosphatidylserine
serine
Important phospholipase in eicosanoid production (cuts at R2 position of phospholipid)
phospholipase A2
Important phospholipase in IP3 signaling pathway
phospholipase C
Phopholipase A2 releases arachidonic acid
from the 2-position of phospholipids to initiate (blank) production. (blank) represses phopholipase synthesis –long acting anti-inflamatory steroid.
eicosanoid; Cortisone
Components of a sphingolipid
sphingosphine
fatty acid
base
What two things come together before being activated by a fatty acid to form ceramide?
palmitoyl-CoA and serine
a sphingosine with an acyl (FA) group
ceramide
Why is a serine necessary for the sphingosine backbone?
provides the amine
Ceramide can form sphingomyelin through the addition of what?
Ceramide can form cerebrosides through the addition of what?
phospho-choline head group
sugar added from UDP-galactose
A glucocerebroside is a ceramide with a (blank) residue
glucose
A galactocerebroside is a ceramide with a (blank) residue
galactose
Where are glucocerebrosides and galactocerebrosides primarily found?
In brain tissue
Galactocerebroside with a sulfate group
sulfolipid
Disease resulting from inability to degrade a ganglioside, so lysosomes fill up with undegraded gangliosides and cause weakness, retardation, blindess, and death by age 3 or 4.
Tay-Sachs disease
Tay-Sachs is an inability to breakdown (blank)
gangliosides
What’s the enzyme deficiency in Tay-Sachs disease?
hexosaminidase A
