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What are the three groups of lipids:
Three groups of lipids: structural (membrane), storage, and other.
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Lipid structural features:
- Backbones: sphingosine or glycerol
- FA: hydrocarbons
- Complex rings: cholesterol and derivatives, cofactors, singnaling molecules, vitamins.
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Define storage lipids:
Storage lipids: contain fatty acids and oils, built to make them stable (i.e. inert) and easy to dissasemble.
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Define structural lipids:
Structural lipids: contains phospholipids and sterols, built to provide stability and mobility for membrane components.
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Define "other" lipids:
Other: contains cofactors, electron carriers, pigments, hydrophobic anchors, hormones, intracellular messangers. They are built to provide special functions.
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What storage lipid is noted? describe the structure:
- Triacylglycerol:
- It has a glycerol backbone and three acyls(FA).
- Ester bonds.
- Hydrophobic, nonpolar.
- Cleaved by lipases: hydrolize the ester linkages.
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What are the three classes of membrane lipids?
glycerophospholipids, sphingolipids, and sterols.
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define glycerophospholipids:
two FA joined to glycerol
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define sphingolipids:
one FA + one fatty amine (sphingosine)
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define sterols:
Rigid core of 4 fused hydrocarbon rings. No backbone.
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two types of membrane lipids:
phospholipids and glycolipids.
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what are waxes?
esters of long chain saturated/unsaturated FA + long chain of alcohols.
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describe phospholipids:
some glycerophospholipids and sphingolipids with a polar head group + FA.
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describe glycolipids:
some sphingolipids with a simple sugar instead of phosphate.
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Structure of glycerophospholipids: what is ita parent molecule?
- C1 FA
- C2 FA
- C3 phosphate + polar head group (alcohol)
- parent molecule: phosphatidic acid.
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Structure of sphingolipids: what is its parent molecule?
- parent molecule: ceramide
- 3-carbon backbone.
- Sphingosine + long chain FA + polar head group.
- Note: head group joined by phosphodiester or glycosidic linkage.
- FA is attched to an amide at C2.
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What are the three classes of sphingolipids and what do they differ in?
- Differ in head groups.
- Classes: sphingomyelins, glycosphingolipids, and gangliosides.
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Define sphingomyelins:
- class of sphingolipids.
- head group = phosphocholine.
- this class is a phospholipid.
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Define glycosphingolipids,
- class of sphingolipids.
- mostly on outter face of plasma membrane
- Head groups have one or more sugars on C1 ceramide.
- cerebrosides: one sugar on ceramide
- globosides: more than one sugar on ceramide
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define gangliosides:
- class of sphingolipids.
- polar head groups = oligosaccharides
- one or more N-acetylneraminic acids
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Galactolipids:
- dfferent from glcosphingolipids; no nitrogen
- no phosphate
- 1,2 diacylglycerol + 1 or 2 galactose at C3
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How to degrade phospholipids and sphingolipids
- phospholipases cleave phospholipids. product is lysophospholipid, function is signaling.
- Different signaling molecules due to 4 different phospholipases
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What is a sterol, structure, roles:
- nucleus: 4 rings.
- role as structure.
- cholesterol is amphipathic. alters membrane fluidity. at high temp, decreases fluidity, at low temp, increases fluidity.
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