Question

What is the energetic price, in ATP equivalents, of breaking down palmitic acetyl-CoA and then re-synthesizing it? For Full Credit, you must show all your calculations clearly

Answer 1

Palmitic acetyl CoA(C16 fatty acyl group) involves 7 rounds of beta oxidation yeilding 7FADH2 , 7NADH and 8 acetyl-CoA.  

8acetyl CoA×10=80 ATP, 7FADH2×1•5=10•5 ATP, 7NADH×2•5=17•5 ATP. Total 108 ATP but in fatty acid activation 2 mol ATP is spend so, net yield is (108-2) =206 ATP.

In re-synthesizing process first formation of seven malonyl CoA molecules from 7 acetyl CoA, in this process 7 mol ATP spend then seven cycles of condensation and reduction, in this process one acetyl CoA, 14 NADPH needed. 8 acetyl CoA×10=80 ATP, 14 NADPH×3•5=49 ATP, 7 ATP. Total ATP needed for palmitic acetyl CoA synthesis is (80+49+7) =136 mol ATP.