How many Acetyl CoA units are produced from a C18 fatty acid after complete beta oxidation?

To determine the number of Acetyl CoA units produced from the complete beta-oxidation of a C18 fatty acid, it is important to understand the process of beta-oxidation itself. During beta-oxidation, fatty acids are broken down into Acetyl CoA units, and each cycle of beta-oxidation involves the removal of two carbon atoms in the form of Acetyl CoA.

For a fatty acid, the number of Acetyl CoA units produced can be calculated using the formula:

(Number of carbons / 2) = Number of Acetyl CoA units.

In this case, with a C18 fatty acid:

18 carbons / 2 = 9 Acetyl CoA units.

However, during beta-oxidation, the process also produces FADH2 and NADH, and it typically requires the removal of 1 water molecule in each cycle, which leads to additional steps that are often overlooked in simple calculations. Nonetheless, the key point is that each complete cycle of beta oxidation removes two carbons and produces one Acetyl CoA, and with an 18-carbon fatty acid, the net production after accounting for the final set of carbons also aligns with producing