Chapter 9: Lipids and Membranes Flashcards
The 8 major categories of lipids include:
Fatty acids
Glycerolipids
Glycerophospholipids
Sphingolipids
Sterol lipids
Prenol lipids
Saccharolipids
Polyketides
The universal form of stored energy in nature is?
Fat and oils in the form of fatty acids
What does the oxidation of fatty acids yield?
CO2 and H2O
*like combustion of hydrocarbon fuels
Fatty acid structure:
a.) carboxylic end
b.) hydrocarbon chain of 4-36 carbons
c.) polyunsaturated
What lipids do humans require in our diet?
omega-3 PUFA (ALA) to synthesize EPA and DHA which is important for cell function
Are saturated FA’s soluble?
NO, PUFA’s are slightly more soluble in water
What is melting point of fatty acids determined by?
Length of FA and degree of saturation
Saturated= higher MP
Why do saturated FA have higher MP’s?
Due to the tight packing of saturated FAs (unsaturated fats have a loose association)
Discuss fatty acid transport.
FA’s are bound to serum albumin and transported through the circulatory system.
Why are some FA’s harder to transport?
Hard to transport if they are in the ESTER form called triacylglycerols. They are less soluble and diffucult to move.
Triacylglycerols do what?
Simplest lipid constructed from FA’s. TAG is the preferred energy storage and they provide insulation.
Human adipocytes are?
a.) Huge fat droplets that fill the cells.
b.) Stripped down cells with very little functionality.
c.) Hydrolyze TAG with stored enzyme lipase
Why and what are trans fats?
To improve the shelf life of foods, commercial vegetable oils were
subjected to partial hydrogenation which converts cis double bonds to
trans double bonds.
Trans fats increase TAG, LDL, and cholesterol levels in blood causes an inflammatory response
LDL- low density lipoprotein
Strucure of wax?
a.) long chain saturated and unsaturated fatty acids (C14-C36)
b.) head group that consists of long alcohol groups (C16-C30)
MP is 60-100 celsius
How are waxes used in real life?
Marine organisms: as a fuel source, structural features of habitats, waterproof features on skin
Cosmetics and Pharmaceuticals: drugs, lotions, ointments, and polishes
Membrane lipids have a polar and nonpolar end, they are _____
amphipathic
Storage lipids (neutral)
glycerol + 3 fatty acid chains
Membrane lipids - phospholipids - glycerophospholipids
Glycerol + 2 fatty acid chains + (phosphoanhydride + alcohol)
Membrane lipids - phospholipids - sphingolipids
Sphingosine (amine) + 1 fatty acid chain + (phosphoanhydride + choline)
Membrane lipid - glycolipid - sphingolipid
Sphingosine (amine) + 1 fatty acid chain + mono or oligosaccharide
Membrane lipid - glycolipid - galactolipids
Glycerol + 2 fatty acid chains + (mono or oligosaccharide and SO4)
______ are often part of the cell membrane and act as a physical
barrier for polar molecules and ions
Structural lipids
Archael tetrether lipids
2 very long acyl chains are etherlinked to glycerol at both ends
acyl: carbonyl group + R group + functional group
Sterols
composed of 4 rigid fused hydrocarbon rings
What are the 5 general types of membrane lipids?
1.) Glycerophosphilipids
2.) Galactolipids
3.) Archael tetraether lipids
4.) Sphingolipids
5.) Sterols
Why is it so difficult to study the membrane?
Most structural parts are inside the membrane, it’s very hard to see and hydrophobic nature makes it hard to isolate them
Glycerophospholipids that have ether-linked alkenyl chain instead of esterlinked fatty acid
Plasmalogens
Galactolipids predominate where?
Largely stored in the thylakoid membrane of chloroplasts, because phosphate is a limiting reagent in soils
Where is sphingomyelin found?
- a form of sphingolipid
Myelin, a membranous sheath surrounding and insulating axons of neurons
Where are glycosphingolipids are found?
In outer leaflet of plasma membranes, have a sugar on their head group
Where are cerebrosides found?
Neural tissue
Where are globosides found?
Neural tissue but they have more than one sugar gorup
