Question

Arachidonic acid is composed of how many carbon atoms in its chain?

• A. 20
• B. 18
• C. 16
• D. 12

Hint:

Memorize the carbon numbers for key fatty acids: Palmitic (16:0), Stearic (18:0), Oleic (18:1), Linoleic (18:2), and \textbf{Arachidonic (20:4)}.

Answer 1

The Correct Option is A

Step 1: Recall the structure of common fatty acids. Fatty acids are classified by their carbon chain length and number of double bonds.
Step 2: Specifically identify Arachidonic acid. Arachidonic acid is a polyunsaturated omega-6 fatty acid. Its lipid shorthand notation is 20:4(n-6), which indicates:

20 carbons in its chain.
4 cis-double bonds.
The first double bond is at the 6th carbon from the omega end. \end{itemize} Therefore, it is composed of 20 carbon atoms.