Question

1. Draw the structure and calculate the yield, in ATP equivalents, upon complete aerobic oxidation of lauric acid (12:0). 2. Draw the structure and calculate the yield, in ATP equivalents, upon complete aerobic oxidation of myristic acid (14:0). 3. Draw the structure and calculate the yield, in ATP equivalents, upon complete aerobic oxidation of arachidir acid (200)

Answer 1

Structure of ATP Equivalents on completion of Aerobic Oxidation of Lauric Acid :

Acetyl-CoA generated by the beta-oxidation pathway enters the mitochondrial TCA cycle, where is further oxidized to generate NADH and FADH2. The NADH and FADH2 produced by both beta oxidation and the TCA cycle are used by the mitochondrial electron transport chain to produce ATP. Complete oxidation of one palmitate molecule (fatty acid containing 16 carbons) generates 129 ATP molecules.

Structure of ATP Equivalents on completion of Aerobic Oxidation of Myristic Acid

The complete aerobic oxidation of glucose is coupled to the synthesis of as many as 36 molecules of ATP:

Glycolysis, the initial stage of glucose metabolism, takes place in the cytosol and does not involve molecular O2. It produces a small amount of ATP and the three-carbon compound pyruvate. In aerobic cells, pyruvate formed in glycolysis is transported into the mitochondria, where it is oxidized by O2 to CO2. Via chemiosmotic coupling, the oxidation of pyruvate in the mitochondria generates the bulk of the ATP produced during the conversion of glucose to CO2. In this section, we discuss the biochemical pathways that oxidize glucose and fatty acids to CO2 and H2O

The overall reaction for one cycle of beta oxidation is:

Cn-acyl-CoA + FAD + NAD+
+ H
2O + CoA → Cn-2-acyl-CoA + FADH
2 + NADH + H+
+ acetyl-CoA

Due to  beta-oxidation which fatty acid molecules are broken down in the cytosol in prokaryotes and in the mitochondria in eukaryotes to generate acetyl-CoA, which enters the citric acid cycle, and NADH and FADH2, which are co-enzymes used in the electron transport chain.

It is named as such because the beta carbon of the fatty acid undergoes oxidation to a carbonyl group. Beta-oxidation is primarily facilitated by the mitochondrial trifunctional protein, an enzyme complex associated with the inner mitochondrial membrane, although very long chain fatty acids are oxidized in peroxisomes.