Question

I am having a hard time understanding these two questions. If someone can explain that would be great.

1) Explain the steps that enables body to metabolize fat to ATP?

2) Write out the amount of ATP, NADH, FADH2 produced in each step of cellular metabolism of a glucose.

Answer 1

Answer 1:

Fats are digested into free fatty acids and glycerol in small intestine due to the action of pancreatic lipase and emulsification of bile. These fatty acids then cross the Intestinal membrane and they combine again to form triglycerides. This then combines with cholesterol to form chylomicrons. This then enters lymphatic system. Then it goes to circulatory system. Through circulatory system then it goes to liver or it gets stored in adipocytes.

The breakdown of fatty acid is called as fatty acid oxidation (beta (β) oxidation) which takes place in cytoplasm. Here fatty acids are converted into fatty acyl CoA. This fatty acyl CoA then gets combined with carnitine to form fatty acyl carnitine which transports fatty acid across the membrane of mitochondria. Once it goes inside the matrix of mitochondria then fatty acyl carnitine is converted back into fatty acyl CoA and then it gets converted into acetyl CoA. This acetyl CoA then enters the Krebs cycle and electron transport chain and ATP gets produced.

For example: A single 18 carbon fatty acid is broken into 9 acetyl CoA molecules which when enters Kreb's cycle and electron transport chain produces 90 ATP.