Which statement about omega-6 fatty acids is true?

Which statement about omega-6 fatty acids is true?

• A. They have their first double bond at the third carbon from the methyl end
• B. They have their first double bond at the sixth carbon from the methyl end, and linoleic acid; can be converted to arachidonic acid; inflammatory.
• C. They are always anti-inflammatory
• D. They lack double bonds

Answer: (B)

Omega-6 fatty acids are defined by having their first double bond six carbons from the methyl (omega) end. Linoleic acid, the primary dietary omega-6, fits this pattern. It can be desaturated and elongated to arachidonic acid, which then serves as a precursor to eicosanoids that promote inflammatory responses. So this statement captures both the naming rule and the metabolic path to arachidonic acid with inflammatory potential, making it true. The other ideas don’t fit: the first double bond at the third carbon describes omega-3 fats, not omega-6; lacking double bonds would make them saturated fats; and omega-6 fats are not always anti-inflammatory—they can be pro-inflammatory through arachidonic acid–derived mediators.

Omega-6 fatty acids are defined by having their first double bond six carbons from the methyl (omega) end. Linoleic acid, the primary dietary omega-6, fits this pattern. It can be desaturated and elongated to arachidonic acid, which then serves as a precursor to eicosanoids that promote inflammatory responses. So this statement captures both the naming rule and the metabolic path to arachidonic acid with inflammatory potential, making it true.

The other ideas don’t fit: the first double bond at the third carbon describes omega-3 fats, not omega-6; lacking double bonds would make them saturated fats; and omega-6 fats are not always anti-inflammatory—they can be pro-inflammatory through arachidonic acid–derived mediators.