Chap 11-Lipids Flashcards
Lipids def
Water insoluble molecules that are highly soluble in organic compounds. Widely used to store energy. Key components of membranes. roles in signal-transduction pathways.
What are the five classes of lipids?
- Free fatty acids
- Triacylglycerols
- Phospholipids
- Glycolipids
- Steroids
Saturated fatty acids
Composed of only single bonds, because every carbon atom is attached to four other atoms,
WHat are the two key roles for fatty acids?
- for fuels
- building blocks for membreane lipids.
Unsaturated fatty acids
fatty acids with one or more double or triple bonds. Have a lower melting point
what afctors determine the melting point if fatty acids
the chain length and the saturation, shorter chain length and more double bonds decrease melting point
triacylglycerols
formed by the attachement of three fatty acid chains to a glycerol molecule for storage. Process called esterfication. while were sleeping, fatty acids are cleaved from the triacylglycerol and carried to the cells.
Phospholipids
Abundant in all biologocal membranes. constructed from four components, one or more fatty acids, a platform for them to attach, a phosphate, and an alcohol attached to the phosphate.
phosphoglycerides
phospholipids in which the backbone is glycerol.
glycolipids
sugar-containing lipids. ubiquitous in all cell membranes and they play a role in cell-cell interactions.
Glycolipids are oriented in an asymmetric fashion in membranes with the sugar residues always on the extracellular side of the membrane.
Steroids
Function as powerful hormones , facilitate the digestion of lipids in the diet, and key membrane components. exhibit a cyclic rather than linear structure.
An example cholesterol, is important in maintaining proper membrane fluidity.
Distinguish between phosphoglycerides and trialcylglycerols
Triacylglycerols consist of three fatty acidchains attached to a glycerol backbone, they are a storage form of fuel. Phophoglycerides consist of two fatty acid chains attached to a glycerol backbone. The remaining alcohol of the glycerol is bonded to a phosphate, which is bonded to an alcohol, these are membrane components.
What structural features differentiate sphingolipids from phosphoglycerides?
The backbone in phosphoglycerides is glycerol where as in sphingolipids is sphingosine. In sphingolipids, one of the fatty acids is linked to the sphingosine by an amide bond.
What are some molecules that form the polar head of phospholipids?
Examples are serine, ethanolamine, choline, glycerol, inositol
