lipid structure and function Flashcards
lipids are
amphipathic - they have both hydrophilic (polar head) and hydrophobic (nonpolar tail)
lipids are made of
fatty acids + glycerol or sphingosine derivative
the bond between lipid monomers are
esters
basics of lipid structure
hydrocarbon + carboxyl
primary hydrophobic deterinant in lipids
fatty acids can be ____ or ____
saturated or unsaturated
pKa of carboxyl on fatty acids
4.5
fatty acids: melting point
- saturated
- unsaturated
- higher
- lower
fatty acids: flexibility
- saturated
- unsaturated
- high
- low
fatty acids: C-C bonds
- saturated
- unsaturated
- all
- many
fatty acids: C=C bonds
- saturated
- unsaturated
- none
- cis and trans
in saturated fatty acids, the shape of the hydrocarbon is
linear
in unsaturated fatty acids, the shape of the hydrocarbon in:
- cis
- trans
- bent more
- bent less
the dietary source of saturated fatty acids is
animal fats (e.g. butter, lard, etc)
the dietary source of cis unsaturated fatty acids is
plant oils (e.g. olive oil) and omega fatty acids
the dietary source of trans unsaturated fatty acids is
processed fats
examples of saturated fatty acids
lauric, myristic, palmitic, stearic, arachidic, behenic, lignoceric acids
examples of cis unsaturated fatty acids
palmitoleic, oleic, linoleic, linolenic, arachidonic acids, EPA, and DHA
examples of trans unsaturated fatty acids
partially hydrogenated oils
fatty acids are numbered from
carboxyl-end (alpha-C) to methyl-end (w-C)
fatty acid nomenclature: first position
- n =
- cis or trans =
- saturated
- type of double bond(s), each one indicated
fatty acid nomenclature: 5th position
- oic acids =
- oate =
- oic acids = protonated/acid
- oate = deprotonated/conjugate base
omega fatty acids are named
for the position of the double bond closest to the methyl (w) end of the fatty acid
omega-3 fatty acids
linolenic acid (18:3)/ALA
stearidonic acid (18:4)/SDA
docosapentaenoic acid (22:5)/DPA
Iecosapentaenoic acid (20:5)/EPA
docosahexaenoic acid (22:6)/DHA
omega-6 fatty acids
linoleic acid (18:2)/LA
arachidonic acid (20:4)/AA
docosapentaenoic acid (22:5)/DPA
which 2 fatty acids cannot be synthesized by humans
LA/Linoleic acid (18:2/w-6)
ALA/Linolenic acid (18:3/w-3)
ALA is inefficiently converted to 2 other omega fatty acids
EPA/Eicosapentaenoic acid (20:5/w-3)
DHA/docosahexaenoic acid (22:6/w-3)
why are omega fatty acids important
are used in cell membrane and other important lipids
are a common energy source
promote good health by improving cardiovascular health
fatty acid: common names:
first number in parenthesis:
second number in paraenthesis:
total number of carbons
total number of double bonds (total number of unsaturations)
essential fatty acids
LA/Linoleic acid (18:2/w-6)
ALA/Linolenic acid (18:3/w-3)
EPA/Eicosapentaenoic acid (20:5/w-3)
DHA/Docosahexaenoic acid (22:6/w-3)
laurate:
number of carbons
number of double bonds
12
0
myristate:
number of carbons:
number of double bonds:
number of carbons: 14
number of double bonds: 0
palmitate:
number of carbons:
number of double bonds:
number of carbons: 16
number of double bonds: 0
Stearate:
number of carbons:
number of double bonds:
number of carbons: 18
number of double bonds: 0
arachidate:
number of carbons:
number of double bonds:
number of carbons: 20
number of double bonds: 0
behenate:
number of carbons:
number of double bonds:
number of carbons: 22
number of double bonds: 0
lignocerate:
number of carbons:
number of double bonds:
24
0
palmitoleate:
number of carbons:
number of double bonds:
16
1
oleate:
number of carbons:
number of double bonds:
18
1
linoleate:
number of carbons:
number of double bonds:
18
2
linolenate:
number of carbons:
number of double bonds:
18
3
arachidonate:
number of carbons:
number of double bonds:
20
4
EPA/Eicosapentaenoic acid:
number of carbons:
number of double bonds:
20
5
DHA/Docosahexaenoic acid:
number of carbons:
number of double bonds:
22
6
fatty acids (with single hydrocarbon tail) can form
micelles
fatty acids (phospholipids-with multiple hydrocarbon tails) can form
a bilayer
fatty acids in micelles are
wedge-shaped and tend to form spherical micelles
phosophilips are more cylindrical and pack together to form
a bilayer structure
____ are the majority component of cell membranes
glycerophospholipids
common acohols added to glycerophospholipids are
- amino acids = serine
- sugar-derivatives = inositol, glycerol
- organics = ethanolamine, choline
____ attach a fatty acid to an amine
sphingophospholipids
____ are important for ABO blood type antigens and cell signaling
glycosphingolipids
____ are found in plants and bacteria, but rarely in animals
glycoglycerolipids
____ is an important sterol
cholesterol
____ are waxy. in addition to being found in cell membranes, they are intermediates for the other sphingolipids
cerimides
the polar regions on waxes are very ____ , therefore predominantly hydrophobic nature of the molecule will ____ water
small
repel
____ are the most common form of fat storage molecules
triacylglycerols (TAGs)
triacylglycerols are composed of
glycerol + 3 fatty acids
archaeal lipid membranes contain
branched fatty acids