Beta oxidation

What is the primary metabolic pathway for the degradation of fatty acids?

Beta oxidation.

Where does beta oxidation occur in the cell?

In the mitochondrial matrix.

What is the major source of energy for the heart and skeletal muscle during fasting or endurance exercise?

Beta oxidation of fatty acids.

What must happen to long-chain fatty acids before they enter beta oxidation?

They must be activated in the cytosol and transported across the inner mitochondrial membrane.

What is the role of Acyl-CoA synthetase in fatty acid metabolism?

It converts fatty acids into Fatty Acyl-CoA.

What is the reaction catalyzed by Acyl-CoA synthetase?

Fatty Acid + CoA + ATP → Fatty Acyl-CoA + AMP + PPi.

How many high-energy phosphate bonds are consumed during fatty acid activation?

Two high-energy phosphate bonds.

What enzyme converts Fatty Acyl-CoA to Acyl-carnitine?

CPT-I.

What enzyme converts Acyl-carnitine back to Acyl-CoA?

CPT-II.

What are the four stages of beta oxidation?

Oxidation (dehydrogenation), Hydration, Oxidation, Thiolysis.

What happens during the oxidation stage of beta oxidation?

Hydrogen atoms are removed, forming a trans-double bond and reducing FAD to FADH2.

What does water addition during the hydration stage create?

A hydroxyl group on the beta carbon, forming L-3-hydroxyacyl-CoA.

What is produced during the third stage of beta oxidation?

NADH + H^+ through the oxidation of the hydroxyl group to a ketone group.

What is the function of β-ketothiolase during thiolysis?

To split the molecule into one Acetyl-CoA and a new Fatty Acyl-CoA that is two carbons shorter.

How can you calculate the number of Acetyl-CoA produced from a saturated even-chain fatty acid with n carbons?

n/2.

How many cycles occur during the beta oxidation of a saturated fatty acid?

(n/2) - 1 cycles.

What is the total ATP yield from the complete oxidation of palmitate (C16)?

106 ATP after accounting for activation costs.

How many FADH2 and NADH are produced from palmitate oxidation?

7 FADH2 and 7 NADH.

What is the contribution of Acetyl-CoA to ATP yield from the Citric Acid Cycle?

10 ATP per Acetyl-CoA.

What is the contribution of FADH2 to ATP yield?

1.5 ATP per FADH2.

What is the contribution of NADH to ATP yield?

2.5 ATP per NADH.

What is the net energy yield of ATP from beta oxidation of palmitate after considering activation cost?

106 ATP.

Define the Carnitine Shuttle in fatty acid metabolism.

The mechanism that transports fatty acyl-CoA into the mitochondrial matrix for beta oxidation.

What is the final product of the thiolysis stage of beta oxidation?

Acetyl-CoA and a fatty acyl-CoA that is two carbons shorter.

What is the significance of beta oxidation for energy production?

It provides a major source of energy from fatty acids during fasting and exercise.