Question

How many molecules of ATP are generated when stearic acid , an 18-carbon saturated fatty acid, is completely oxidized via the beta-oxidation pathway in the mitochondria?

a) 112
b) 129
c) 146
d) 163

Answer 1

(c) . 146

Step-by-step explanation:

To calculate the ATP generated in complete beta-oxidation of stearic acid (an 18-carbon saturated fatty acid ),

number of rounds of beta-oxidation =
`n/2 - 1` ,

where ,n is number of carbon present in fatty acid since , n= 18 in give fatty acid

number of rounds of beta-oxidation =
`18/2 - 1 = 8`

8 rounds of beta-oxidation gives :-

-8
`NADH`

-8
`FADH_(2)`

-8
`Acetyl-CoA` +
`Acetyl-CoA`

Each rounds of beta oxidation gives 17 ATP , So 8 rounds of beta- oxidation gives 17 × 8 = 136 ATP , while theres's an extra
`Acetyl-CoA` which also undergoes in Krebs cycle along with other 8
`Acetyl-CoA` , though this extra
`Acetyl-CoA` produce 12 ATP . While 2 molecules of ATP is consumed in activation of fatty acid , So total energy generated in beta-oxidation of stearic acid is 146 .