BCH 4053 Exam 2
Saturated fatty acids lack double bonds between the individual carbon atoms, tend to be solid at room
temperature, and come from animal sources.
In unsaturated fatty acids there is at least one double bond in the fatty acid chain, are usually liquid, and
from plant sources. ANS:What is the difference between saturated and unsaturated fatty acids?
Double bonds cause the hydrocarbon chain to bend. Therefore, the fatty acids cannot compact tightly
together, reducing the van der Waals interaction between the fatty acids.
The melting point of fatty acids is also affected by chain length. The LONGER the hydrocarbon chain is,
the HIGHER the melting point. ANS:What effect do you think acyl chain length has on fatty acid melting
points?
The geometry of the double bond is almost always a cis configuration in natural fatty acids. These
molecules do not "stack" very well. The intermolecular interactions are much weaker than saturated
molecules.
As a result, the melting points are much LOWER for unsaturated fatty acids. ANS:What effect do you
think double bonds have on melting points?
Energy storage, thermal insulation, structural components of membranes, protective coatings of plants
and insects, hormonal regulation, chemical signaling of various kinds, enzymatic cofactors, electron
carriers ANS:Lipid Functions
Soluble in organic solvents, poorly soluble or insoluble in water, amphipathic structure ANS:Chemical
Properties of Lipids
Major part of molecule is non-polar, but polar portion interacts with water. ANS:Amphipathic Structure
of Lipids
,Carboxylic acid connected to long hydrocarbon chain. ANS:Chemical Properties of Fatty Acids
Typically 14-20 carbons long (usually even number of carbons because synthesized by joining of C2
precursors) and differ in length and degree of saturation (number of double bonds). ANS:Structure of
Carboxylic Acid connected to long hydrocarbon chain
Saturated and Unsaturated ANS:Two Classes of Fatty Acids
Saturated Fatty Acid ANS:A fatty acid in which all carbons in the hydrocarbon tail are connected by
single bonds, thus maximizing the number of hydrogen atoms that can attach to the carbon skeleton.
Very flexible but usually extended.
Generally even number of C atoms.
Unsaturated Fatty Acid ANS:A fatty acid possessing one or more double bonds between the carbons in
the hydrocarbon tail.
Such bonding reduces the number of hydrogen atoms attached to the carbon skeleton.
Monounsat and polyunsat
Monounsat ANS:One double bond in chain
Polyunsat ANS:More than one double bond
, Introduces 30 degree bend in hydrocarbon chain
Don't package well against each other ANS:Unsaturated lipid usually have double bonds in cis
configuration
Stearic Acid ANS:
Oleic Acid ANS:
Linoleic acid ANS:
a-Linolenic Acid ANS:
Palmitic Acid ANS:
Arachidonic Acid ANS:
Saturated ANS:Fatty acids that pack tightly and form more rigid structures
Unsaturated ANS:Fatty acids that bend and pack in a less ordered way, with greater potential for
motion
Melting Points ANS:Depends on molecular weight and saturation
A smaller molecular weight and in unsaturated fatty acids. ANS:Lower melting point occurs with...
Saturated fatty acids lack double bonds between the individual carbon atoms, tend to be solid at room
temperature, and come from animal sources.
In unsaturated fatty acids there is at least one double bond in the fatty acid chain, are usually liquid, and
from plant sources. ANS:What is the difference between saturated and unsaturated fatty acids?
Double bonds cause the hydrocarbon chain to bend. Therefore, the fatty acids cannot compact tightly
together, reducing the van der Waals interaction between the fatty acids.
The melting point of fatty acids is also affected by chain length. The LONGER the hydrocarbon chain is,
the HIGHER the melting point. ANS:What effect do you think acyl chain length has on fatty acid melting
points?
The geometry of the double bond is almost always a cis configuration in natural fatty acids. These
molecules do not "stack" very well. The intermolecular interactions are much weaker than saturated
molecules.
As a result, the melting points are much LOWER for unsaturated fatty acids. ANS:What effect do you
think double bonds have on melting points?
Energy storage, thermal insulation, structural components of membranes, protective coatings of plants
and insects, hormonal regulation, chemical signaling of various kinds, enzymatic cofactors, electron
carriers ANS:Lipid Functions
Soluble in organic solvents, poorly soluble or insoluble in water, amphipathic structure ANS:Chemical
Properties of Lipids
Major part of molecule is non-polar, but polar portion interacts with water. ANS:Amphipathic Structure
of Lipids
,Carboxylic acid connected to long hydrocarbon chain. ANS:Chemical Properties of Fatty Acids
Typically 14-20 carbons long (usually even number of carbons because synthesized by joining of C2
precursors) and differ in length and degree of saturation (number of double bonds). ANS:Structure of
Carboxylic Acid connected to long hydrocarbon chain
Saturated and Unsaturated ANS:Two Classes of Fatty Acids
Saturated Fatty Acid ANS:A fatty acid in which all carbons in the hydrocarbon tail are connected by
single bonds, thus maximizing the number of hydrogen atoms that can attach to the carbon skeleton.
Very flexible but usually extended.
Generally even number of C atoms.
Unsaturated Fatty Acid ANS:A fatty acid possessing one or more double bonds between the carbons in
the hydrocarbon tail.
Such bonding reduces the number of hydrogen atoms attached to the carbon skeleton.
Monounsat and polyunsat
Monounsat ANS:One double bond in chain
Polyunsat ANS:More than one double bond
, Introduces 30 degree bend in hydrocarbon chain
Don't package well against each other ANS:Unsaturated lipid usually have double bonds in cis
configuration
Stearic Acid ANS:
Oleic Acid ANS:
Linoleic acid ANS:
a-Linolenic Acid ANS:
Palmitic Acid ANS:
Arachidonic Acid ANS:
Saturated ANS:Fatty acids that pack tightly and form more rigid structures
Unsaturated ANS:Fatty acids that bend and pack in a less ordered way, with greater potential for
motion
Melting Points ANS:Depends on molecular weight and saturation
A smaller molecular weight and in unsaturated fatty acids. ANS:Lower melting point occurs with...
