Organic Chemistry : Organic Chemistry
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Example Questions
Example Question #2 : Biological Molecules
What is the name of the pictured fatty acid?
Linoleic acid
Eicosapentaenoic acid
Oleic acid
Arachidonic acid
Palmitoleic acid
Arachidonic acid
The pictured structure represents arachidonic acid due to the 20-carbon carboxylic acid chain with characteristic unsaturated (double) bonds after carbons 5, 8, 11, and 14.
Example Question #2 : Biological Molecules
Other than the traditional numerical system, the X marking the terminal carbon in the structure shown here can be labeled how?
Omega-18
Omega-1
Gamma-18
Alpha-18
Alpha-1
Omega-1
Fatty acids can be labeled numerically from 1-X, or they can be labeled in reverse starting with omega-1 as the terminal carbon.
Example Question #251 : Organic Chemistry
Identify the common name of the fatty acid shown here.
Oleic acid
Palmitic ccid
Arachidonic acid
Myristic acid
Linoleic acid
Oleic acid
Oleic acid is a fatty acid consisting of 18 carbon molecules and a single unsaturated (double) bond after carbon 9, as pictured.
Example Question #3 : Biological Molecules
What type of lipid is shown below?
Steroid
Phospholipid
Triglyceride
Fatty acid
Phosphatidylcholine
Triglyceride
A triglyceride consists of three fatty acid chains bound to a glycerol backbone via ester bonds, as shown by the pictured structure.
Example Question #253 : Organic Chemistry
Three fatty acid chains can be bound to a glycerol backbone via ester bonds to form a triglyceride. What type of chemical reaction is this?
Hoffman elimination
Hydrolysis
Condensation
Oxidation-reduction
Markovnikov
Condensation
The reaction described is an esterification in which water is a product—as is characteristic of a condensation reaction—and in which an ester bond is formed to connect the fatty acid chain and the glycerol molecule.
Example Question #4 : Biological Molecules
An unknown molecule was found to have a molecular formula of 
fatty acid
triaclyglycerol
None of these
steroid
None of these
This question is a little bit tricky. At first glance, we would jump to the conclusion that this molecule is a long hydrocarbon chain attached to a carboxylic acid and, therefore, a fatty acid. The premise is correct. However, our conclusion is false because, by convention, a fatty acid must contain a carbon chain of at least 12 carbons. The given formula does not match the description for a steroid or triacylglycerol. The correct answer is none of these.
Example Question #5 : Biological Molecules
What is the primary biological function of a fatty acid?
To serve as a water barrier on the outside of leaves and feathers
All of these
To serve as a medium for energy storage
To serve as a medium for the derivation of other important lipids
To serve as a medium for the derivation of other important lipids
The primary biological function of a fatty acid is to serve as a medium for the derivation of other important lipids such as waxes, triacylglycerols, phospholipids, and other necessary lipids.
Example Question #2 : Biological Molecules
Before the advent of synthetic soap, hand soap was made from animal fat, namely triacylglycerols. What property of triacylglycerols make them an ideal component in hand soap?
None of these
The presence of hydrophobic tails and hydrophilic heads that work to dissolve into and remove dirt/grease on the skin
The ability to engulf dirt/grease on skin
The ability to engulf and digest harmful bacteria on skin
The presence of hydrophobic tails and hydrophilic heads that work to dissolve into and remove dirt/grease on the skin
A triacylglycerol is derived from the hydrolysis of glycerols and fatty acids. Triacylglycerols have hydrophobic hydrocarbon tails and hydrophilic heads (amphipathic). The hydrophobic tails dissolve into dirt/grease on the skin while the hydrophilic tails work with running water to suspend and remove the dissolved impurities.
Example Question #9 : Help With Organic Lipids
Based on the formula and structure of this molecule, this molecule can be classified as a __________.
protein
fatty acid
wax
complex sugar
wax
The correct answer is the lipid, wax. Lipids can often be identified based on their structure alone. The general structure of wax is an ester with two long carbon chains on each end of the ester, as seen in this problem. Additionally, fatty acids can be identified simply as long carbon chains with a carboxylic acid on one end, while the general structure of steroids can be seen as four connected hydrocarbon rings.
Example Question #11 : Help With Organic Lipids
The following terpene is classified as which of the following?
Monoterpene
Monoterpenoid
Eicosanoid
Hemiterpene
Diterpene
Monoterpene
The molecule's skeletal structure contains two isoprene (2-methylbutyl) units, and therefore the molecule is a monoterpene.
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