For an 18 carbon fatty acid, how many rounds of beta oxidation are required?

In the process of fatty acid metabolism, specifically during beta-oxidation, each round of the cycle removes two carbon atoms from the fatty acid chain and breaks it down into acetyl CoA units.

For an 18-carbon fatty acid, the breakdown process begins with the fatty acid being converted into multiple acetyl CoA molecules. Each round requires the fatty acid to lose two carbon atoms, hence with 18 carbons, after the first round you will have 16 carbons left. Continuing this process, each subsequent round reduces the carbon count by two until there are 2 carbons remaining, which then forms the final acetyl CoA.

To determine the number of rounds needed:

• Start with 18 carbons.
• Each round reduces the chain by 2 carbons.
• To get to 2 carbons left (as the last acetyl CoA), you can think of it this way: It takes 1 less round than the number of acetyl CoA molecules produced.

Since acetyl CoA units are produced from every two carbons, an 18-carbon fatty acid will yield 9 acetyl CoA molecules when fully oxidized (18/2 = 9).

It takes 8 rounds