# Do unsaturated fatty acids with an odd number of carbons exist?

Does this fatty acid even exist?

• Biosynthesis adds two carbons at a time, so this less likely than something that's even. – Zhe Dec 12 '16 at 13:03
• You speak of saturated fatty acids where even number of carbons is more abundant then odd number. But in the case of unsaturated fatty acids, does one exist in nature with an odd number of carbons in its chain? – EmmaF Dec 12 '16 at 13:05
• Interesting question, but the biosynthesis happens via the unsaturated acid anyway. If nature wants the saturated version, it simply performs the appropriate reduction of (what happens to be, at the time) an $\alpha,\beta$-unsaturated carbonyl. – Zhe Dec 12 '16 at 14:03