Chem Exam 3 Flashcards
What are fatty acids?
Carboxylic acids that typically contain between 12 and 20 carbon atoms.
What is the structure of fatty acids?
Fatty acids contain a head and a tail.
The tail contains one CH3 and fourteen CH2.
The head contains one C = O and one C – OH
What does saturated mean?
A saturated fatty acid has only single bonds joining the carbon atoms in their hydrocarbon tails.
What does monounsaturated mean?
Monounsaturated fatty acids have just ONE carbon-carbon double bond.
What does polyunsaturated mean?
Polyunsaturated fatty acids have TWO or more double bonds.
What is an example of a saturated fatty acid?
stearic acid
What is an example of a monounsaturated fatty acid?
oleic acid
What is an example of a polyunsaturated fatty acid?
linoleic acid
linolenic acid
Do unsaturated fatty acids melt and boil at higher or lower temps?
Unsaturated fatty acids melt and boil at lower temperatures.
Do melting and boiling points change with the length of saturated fatty acids?
Yes. The melting and boiling points of saturated fatty acids increase with increasing length.
True or false:
For fatty acids with the same number of carbon atoms, the more unsaturated they are, the lower their melting points and boiling points.
TRUE.
Are unsaturated fatty acids liquid or solid at room temp?
Unsaturated fatty acids are LIQUIDS at room temp.
True or false:
Oleic, linoleic, and linolenic acids are all nonessential fatty acids that have 16 carbon atoms.
FALSE.
Oleic, linoleic, and linolenic acids are all ESSENTIAL fatty acids that must be acquired in the diet, and they all have 18 CARBON ATOMS.
What is the structure of oleic acid?
CH3(CH2)7CH=CH(CH2)7CO2H
What is the structure of linoleic acid?
CH3(CH2)4(CH=CHCH2)2(CH2)6CO2H
What is the structure of linolenic acid?
CH3CH2(CH=CHCH2)3(CH2)6CO2H
What is the structure of a wax?
Fatty acid–Alcohol
Define waxes.
Waxes are mixtures of water insoluble compounds, including esters, alcohols, and alkanes.
Define residue.
The part of a reactant molecule that remains when it has been incorporated into a product.
What are triglycerides?
Animal fats and vegetable oils, in which three fatty acid residues are joined to a glycerol residue by ester bonds.
Also known as triacylglycerides.
Fatty acid—
Fatty acid— Glycerol
Fatty acid—
What is the structure of a glycerol?
HO---CH2 ! HO---CH ! HO---CH2
What are the 4 important reactions of triglycerides?
- Hydrogenation
- Partial hydrogenation
- Oxidation
- Saponification
What is hydrogenation?
Hydrogenation is a reduction reaction which results in an addition of hydrogen (usually as H2).
If an organic compound is hydrogenated, what happens?
If an organic compound is hydrogenated, it becomes more ‘saturated’.
True or false:
Hydrogenation does not require a catalyst.
FALSE.
Hydrogenation DOES require a catalyst.
What is partial hydrogenation?
In partial hydrogenation, only some of the carbon-carbon bonds are removed.
Does partial hydrogenation require a catalyst?
YES. Partial hydrogenation does require a catalyst.
What is oxidation?
Oxidation is the loss of electrons during a reaction by a molecule, atom or ion.
What is saponification?
Soap making.
When triglycerides are saponified, glycerol and fatty acid salts (soap) are produced. Soaps are amphipathic compounds that form monolayers and micelles.
The ionic compound NaOH is the source of the OH- used in the reaction shown here.
What are trans fats?
Partial hydrogenation fo unsaturated vegetable oil converts some of the carbon-carbon double bonds from cis into trans isomers.
What is olestra’s basic structure?
Olestra’s basic structure is that of the carbohydrate, sucrose, to which fatty acids have been attached by esterification reactions & via the hydroxyl groups of sucrose.
Define amphipathic.
A term used to describe substances that have both hydrophilic and hydrophobic parts.
True or false:
Membranes are composed of a double layer of amphipathic phospholipids.
TRUE. Membranes are composed of a double layer of amphipathic phospholipids.
What is the structure of a glycerophospholipid?
A glycerophospholipid is made by combining glycerol, two fatty acids, one phosphate group, and one alcohol-containing compound.
What are the 3 types of glycerophospholipids?
- Phosphatidylcholine (lecithin)
- Phosphatidyethanolamine (cephalin)
- Phosphatidylserine
What is [N.C. = (-) + (+) = 0]
Phosphatidylcholine (lecithin)
or
Phosphatidyethanolamine (cephalin)
What is [N.C. = (-) + (+) + (-) = -1]?
Phosphatidylserine
What is the net charge of phosphatidylcholine?
0
What is the net charge of phosphatidyethanolamine?
0
What is the net charge of phosphatidylserine?
-1
What do the 3 types of glycerophospholipids cause?
The 3 types of glycerophospholipids can cause the phospholipid to have different overall net charges.
How are glycolipids formed?
Glycolipids are formed by combining sphingosine, a fatty acid, and a sugar.
What is the structure of sphingosine?
CH3(CH2)11CH2CH=CHCHOH
!
+!
H3NCH
!
CH2OH
What are cerebrosides?
Simple sugars used to produce the glycolipids. They are found at nerve synapses and in the brain.
What are gangliosides?
Another class of glycolipids that are made using a chain of simple sugars. Gangliosides are important in nerve membranes and act as cell surface receptors for hormones and drugs.
True or false:
The sugar molecules in some gangliosides help determine blood type.
TRUE.
The sugar molecules in some gangliosides help determine blood type.