1. Understanding Arachidic Acid
* Arachidic acid is a saturated fatty acid with 20 carbon atoms (C20).
2. Beta-Oxidation Process
* Cycles: Each round of beta-oxidation removes two carbon atoms from the fatty acid chain in the form of acetyl-CoA.
* Yields:
* 1 FADH2 (produces 1.5 ATP)
* 1 NADH (produces 2.5 ATP)
* 1 Acetyl-CoA (enters the citric acid cycle)
3. Calculating the Number of Cycles
* Arachidic acid (C20) will undergo 9 rounds of beta-oxidation (20 carbons / 2 carbons per cycle = 10 cycles, minus 1 because the final 2 carbons are already in acetyl-CoA form).
4. Calculating ATP Yield from Beta-Oxidation
* FADH2 and NADH: 9 cycles x (1 FADH2 + 1 NADH) = 18 FADH2 and 18 NADH
* ATP from FADH2: 18 FADH2 x 1.5 ATP/FADH2 = 27 ATP
* ATP from NADH: 18 NADH x 2.5 ATP/NADH = 45 ATP
5. Calculating ATP Yield from Acetyl-CoA
* Acetyl-CoA: 9 cycles produce 9 Acetyl-CoA molecules
* Citric Acid Cycle: Each Acetyl-CoA produces 10 ATP through the citric acid cycle (2 ATP + 3 NADH + 1 FADH2)
* Total from Acetyl-CoA: 9 Acetyl-CoA x 10 ATP/Acetyl-CoA = 90 ATP
6. Total ATP Yield
* Total ATP: 27 ATP (FADH2) + 45 ATP (NADH) + 90 ATP (Acetyl-CoA) = 162 ATP
Therefore, the beta-oxidation of arachidic acid yields approximately 162 ATP molecules.
