Question

From the designation, 18:2(\(\Delta^{9,12}\)), identify the name of the fatty acid.

• A. Eladic acid
• B. Oleic acid
• C. Linoleic acid
• D. Linolenic acid

Hint:

To remember the 18-carbon unsaturated fatty acids in order:
- Oleic (1 double bond at \(\Delta^9\))
- Linoleic (2 double bonds at \(\Delta^9, \Delta^{12}\))
- Linolenic (3 double bonds at \(\Delta^9, \Delta^{12}, \Delta^{15}\))

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Fatty acid nomenclature uses a standard shorthand format: \(\text{C}:\text{D}(\Delta^{\text{positions}})\), where \(\text{C}\) is the number of carbon atoms, \(\text{D}\) is the number of double bonds, and \(\Delta\) indicates the carbon positions where those double bonds begin.

Step 2: Detailed Explanation:
1. The notation 18:2 indicates an 18-carbon chain with 2 double bonds.
2. The superscript \(\Delta^{9,12}\) places the double bonds between carbons 9-10 and carbons 12-13.
3. Let us evaluate the options: - Oleic acid: 18:1(\(\Delta^9\)) - Monounsaturated fatty acid.
- Elaidic acid: Is the trans-isomer of oleic acid, 18:1(\(\Delta^9\)).
- Linoleic acid: 18:2(\(\Delta^{9,12}\)) - Di-unsaturated essential omega-6 fatty acid.
- Linolenic acid: 18:3(\(\Delta^{9,12,15}\)) - Tri-unsaturated essential omega-3 fatty acid.

Step 3: Final Answer:
The fatty acid designated as 18:2(\(\Delta^{9,12}\)) is linoleic acid.