Question

Tripalmitin is a triacylglyceride whose 3 fatty acid chains are all palmitate. Palmitate is a saturated fatty acid, which has 16 carbons in its chain including the carbonyl carbon. How many electrons will ultimately go to the electron transport chain as a result of the complete catabolism of 1 molecule of tripalmitin? In your answer, indicate where the electrons are coming from (e.g. 2 electrons from NADH generated during glycolysis, 10 electrons transferred directly via ETF to the electron transport chain... etc.).

Answer 1

Hey, Welcome to Chegg. I hope my answer will be of some help to you. Thank you!

For simplicity I am calculating the value for 1 palmitoyl CoA.

Palmitic acid is 16 carbon containing fatty acid.

There will be 7 cycles of beta oxidation for breakdown of each 16 C fatty acid.

From each cycle of beta oxidation, 1 NADH and 1 FADH2 is formed. So, in total 7 NADH and 7 FADH2 will be formed.

1 NADH / FADH2 result in transport of 2 e- to the ETC.

(7 NADH and 7 FADH2 will result in transport of 28 e- to the ETC)

There will be 08 Acetyl CoA formed.

On oxidation by citric acid cycle each acetyl CoA produce 3 NADH + H+ and 1 FADH2.

1 Acetyl CoA= 3 NADH + H+ and 1 FADH2

8 Acetyl coA = 24 NADH + H+ and 8 FADH2.

(24 NADH and 8 FADH2 will result in transport of 64 e-)

So, in total we have (24+7) NADH + H+ and (8+7) FADH2.

We have 31 NADH + H+ and 15 FADH2.

1 NADH + H+ or FADH2 results in transport of 2 e- to the ETC.

31 NADH+ H+ will result in transport of 62 e- to the ETC.

15 FADH2 will result in transport of 30 e- to the ETC.

Total 92 e- are transported to the ETC after complete metabolism of 1 palmitic acid.

So, complete catabolism of tripalmitin or 3 molecules of palmitic acid will result in transport of (92 X3) e- or 276 e-.