| Question |
Answer |
| What is the major phospholipid and surfaceactivecomponent of surfactant. |
Dipalmitoylphosphatidylcholine (DPPC)is the major phospholipid and surfaceactivecomponent of surfactant. |
| What is surfactant? |
Surfactant is a lipoprotein comprisedmainly of glycerophospholipids. |
| How does surfactant work? |
Detergent-like - reduces surface tensionby blocking interaction of H2O moleculesthat line the alveoli. |
| What is the structure of glycerophospholipids? |
Glycerophospholipids are Amphipathic Molecules that Contain a GlycerolBackbone, Two Long-chain Fatty Acids, a Phosphate and a Base/Alcohol |
| Hydroxyl residues at sn-1 and -2 positions are usually in ester linkage with long chain fatty acids of which type? |
sn-1 usually saturated, sn-2 usually polysaturated |
| What role do glycerophospholipids play in plasma lipoproteins (e.g. LDL)? |
Glycerophospholipids Serve as Amphipathic Surface Components of Plasma Lipoproteins |
| Which glycerophospholipid serves as a substrate for LCAT? |
Phosphatidylcholine |
| What lind of glycerophospholipidstether lipoprotein lipase, alkaline phosphatase and acetylcholineesterase to the plasma membrane? |
Inositol-containing glycerophospholipidstether lipoprotein lipase, alkaline phosphatase and acetylcholineesterase to the plasma membrane |
| Which glycerophospholipid has functions associated with hypersensitivity reactions? |
Platelet-activating factor, a highly potent molecule,has functions associated with hypersensitivity reactions. |
| How do glycerophospholipids serve as a reservoir for prostoglandins? |
Arachidonic and linoleic acidsare released from sn-2 position by phospholipases |
| Which secondary messengers do membrane polyphosphoinositidesserve as reservoir for? |
DAG and IP3 |
| What is lecithin another name for? |
phosphatidylcholine |
| When does surfactant secretion begin? |
after 30 weeks gestation |
| How can surfactant be detected in amniotic fluid? |
The lecithin:sphingomyelin ratio |
| What does LCAT do? |
Lecithin:cholesterol acyltransferase catalyzes the transfer of a polyunsaturated fatty acid from the sn-2 position of phosphatidylcholine on LDL to form cholesteryl ester |
| What is the precursor of all glycerophospholipids? |
Phosphatidic acid |
| Name two key regulatory enzymes in glycerophospholipidbiosynthesis and how are they regulated |
Phosphatidate phosphohydrolase (PAPase) & CTP:Phosphocholine cytidylyltransferase – activated byincrease in fatty acyl-CoAs, which promote itstranslocation from cytoplasm to ER. |
| How are glycerophospholipids classified? |
According to the substituent on the phosphate group (e.g. choline) |
| What are glycerophospholipids with an alky or alkenyl in sn-1 position (as opposed to long-chain fatty acid in ester linkage) called? |
Plasmogens (reservoirs of arachidonic acid) |
| What 2 molecules is phosphatidic acid converted to? |
diacylglycerol & CDP-diacylglycerol |
| What 3 molecules can CDP-diacylglycerol be converted to? |
phosphatidylinositol, phosphatidylglycerol-phosphate, and cardiolipin |
| What can phosphatidylglycerol-phosphate be converted to? |
phosphatidylglycerol |
| What can phosphatidylglycerol be converted to? |
cardiolipin (diphosphatidylglycerol) |
| What enzyme converts phosphatidic acid to CDP-diacylglycerol? |
CTP:phosphatidate cytidylyltransferase |
| What can diacylglycerol be converted to? |
triacylglycerol, phosphatidylcholine, and phosphatidylethanolamine |
| What can phosphatidylethanolamine be converted to? |
phosphatidylserine (2-way street) |
| What are the precursors for phosphatidic acid? |
DHAP then converted to Glycerol-3-PO4 |
| What activates PAPase & CTP:phosphatidate cytidylyltransferase? |
Translocation from cytoplasm to membrane (and subsequent activation) is stimulated by long-chain fatty acids and long-chain fatty acyl-CoAs |
| What happens if a glycerophospholipid (PIP2) is cleaved by phospholipase A2? |
Arachidonic acid - prostaglandins, leukotrienes and lipoxins |
| What happens if a glycerophospholipid (PIP2) is cleaved by phospholipase C? |
Inositol triphosphate (IP3) - release of calcium from theendoplasmic reticulum to the cytoplasm |
| What happens if a glycerophospholipid (PIP2) is cleaved by phospholipase D? |
Phosphatidic acid can - increase in intracellular calcium |
Science Vocab 147928
