You have a lipid with 20 carbons 10 carbons and 4 carbons Ho

You have a lipid with 20 carbons, 10 carbons and 4 carbons. How many ATP you get from that?

Solution

The one round of beta oxidation removes one molecule of acetyl-CoA, two pairs of electrons, and four protons from the long-chain fatty acyl–CoA, shortening it by two carbon atoms.
So, the equation can be given as following:
Fatty acyl CoA + CoA + FAD + NAD + H₂O-----> Fatty acyl CoA (2 C shorter) + acetyl-CoA + FADH₂ + NADH + H

Each molecule of FADH₂ produces 1.5 molecules of ATP through ETS while each molecule of NADH forms about 2.5 molecules of ATP. Thus four molecules of ATP are formed for each two-carbon unit removed in one round of beta oxidation.
So, if we take a fatty acid with 20 C, the eight rounds of beta oxidation would produce 40 ATPs as per the following equation:
Fatty acyl CoA (20C) + 9 CoA + 9O2 + 40Pi + 40ADP---->10 acetyl-CoA + 40ATPs + 9H₂O
So, a fatty acid with 20 C would give 40 ATPs.
Since one acetyl CoA gives 10 ATP upon entering the Kreb cycle, the 10 acetyl CoA would give 100 ATPs. This gives total 40+100= 140ATPs per fatty acid (20C). Since 2 ATPs are consumed to activate fatty acid; net gain= 138 ATPs

ATPs gain from lipid with 10C= 138/2= 69 ATPs.
ATP gain from lipid with 4C= 8ATPs (4 ATPs per acetyl CoA direct from beta oxidation) + 20ATPs (Kreb cycle + ETS)= 28ATPs
Net gain = 28-2= 26ATPs.