Chapter 10 Flashcards
Lipids
heterogenous macromolecules
grouped by solubility in nonpolar solvents -
(no “formula”) (contain C & H & a little O)
What are some functions of lipids?
- Energy storage
- Insulation, cushioning
- Cell compartmentalization
- Hormones and signaling
______________ are Hydrocarbon Derivatives
Fatty Acids
What is the nomenclature for unbranched fatty acid
Specifies the chain length and number of double bonds, separated by a colon.
(For example, the 16-carbon saturated palmitic acid is abbreviated 16:0)
What is the equation like nomenclature for fatty acids
The positions of any double bonds, designated Δ (delta), are specified relative to C-1 by a superscript number indicating the lower-numbered carbon in the double bond. By this convention, oleic acid, with a double bond between C-9 and C-10, is designated 18:1(Δ9) (ex a 20-carbon fatty acid with one double bond between C-9 and C-10 and another between C-12 and C-13 is designated 20:2(Δ9,12).
Fatty acid are long, unbranched _____________ (some branching in bacteria)
carboxylic acids
Fatty acids usually have ______ - 20 carbons with even number
12
____________ numbering from C-1 at C=O group; Common names based on C=O with adjacent carbons designated alpha, beta, yamma ; terminal –CH3 is w
IUPAC
Double bonds in the fatty acids are _____ conformation
Cis
The double bonds in fatty acids are usually found at C_, C_, & C_
C9, C12, & C15
The longer the fatty acyl chain and the fewer the double bonds, the _________ the solubility in water.
lower
_____________ fatty acids pack with favorable interactions
Saturated
___________cis fatty acid show less ordered packing due to double bond kink
Unsaturated
Less thermal energy disrupts unsaturated fatty acid packing – more unsaturation which results in a _________ melting point
lower
Rancidity
Double bond cleavage occurs with oxygen exposure
____________ are Fatty Acid Esters of Glycerol
Triacylglycerols
The simplest lipids constructed from fatty acids are the ________________
triacylglycerols
___________________ are composed of three fatty acids, each in ester linkage with a single glycerol
Triacylglycerols
Triacylglycerols Provide Stored Energy and ___________________
Insulation
Membrane lipids are _________________: one end of the molecule is hydrophobic, the other hydrophilic
amphipathic
Membrane lipids form __________
Membrane bilayers
Glycerophospholipids
The hydrophobic regions are composed of two fatty acids joined to glycerol
Galactolipids and sulfolipids
Contain two fatty acids esterified to glycerol, but lack the characteristic phosphate of phospholipids
Archaeal tetraether lipids
Two very long alkyl chains are ether-linked to glycerol at both ends