How many ATP’s are formed in case of stearic acid by (b-oxidation?
**Core Concept**
Fatty acid beta-oxidation is a process by which the body breaks down fatty acids into acetyl-CoA units, which can then be fed into the citric acid cycle to produce ATP. This process involves a series of reactions that result in the formation of a specific number of ATP molecules per fatty acid molecule.
**Why the Correct Answer is Right**
In the case of stearic acid, a 16-carbon fatty acid, beta-oxidation results in the formation of 8 acetyl-CoA units. Each acetyl-CoA unit can enter the citric acid cycle and produce 10 ATP molecules through the process of oxidative phosphorylation. Therefore, the total number of ATP molecules produced from the beta-oxidation of stearic acid is 8 x 10 = 80.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it does not take into account the number of carbon atoms in stearic acid. Fatty acids with an even number of carbon atoms produce a whole number of acetyl-CoA units.
* **Option B:** This option is incorrect because it overestimates the number of ATP molecules produced per acetyl-CoA unit. Each acetyl-CoA unit produces 10 ATP molecules, not 12.
* **Option C:** This option is incorrect because it underestimates the number of ATP molecules produced from the beta-oxidation of stearic acid. With 8 acetyl-CoA units produced, the total number of ATP molecules should be 80, not 60.
**Clinical Pearl / High-Yield Fact**
Remember that the number of ATP molecules produced from fatty acid beta-oxidation is directly related to the number of carbon atoms in the fatty acid molecule. Even-numbered fatty acids produce a whole number of acetyl-CoA units, while odd-numbered fatty acids produce one acetyl-CoA unit and a propionyl-CoA unit.
**Correct Answer:** C. 80