Question

Fatty Acid Catabolism (B Oxidation) Examine Figure 12.15 to answer the questions below. B carbon -SCOA 000000000000000 Fatty acyl CoA of 18C FAD FADH 00000000000000000 scoa @]H40 00000000000000001_scoa or NAD" HO HO -SCOA NAD K.NADH + H NADH+H* 0 0 000-SCOA 0000000000 © COA-SH -SCOA 0 0000000000000000-SCA Fatty acyl CoA of 16C repeats cycle (reactions 1-4)

Answer 1

1. The fatty acyl coA at the bottom of the cycle, containing two carbon less than the fatty acyl CoA at the top of the cycle.

This is beta oxidation process of fatty acids. Each cycle of beta oxidation, produces a 2Carbon unit - Acetyl CoA. This process continues till the fatty acid is completely oxidized.

2. In one cycle 2 reduced nucleotides are produced. NADH and FADH₂ .

3. One molecule of Acetyl-coA produced in one cycle of beta oxidation.

4. Stearic acid contains 18C molecules. It is a saturated fatty acid. So in each cycle it produce 1 Acetyl-coA and will decrease by 2C . There will be 8 cycle to completely oxidized the fatty acid.

a. Total 9 (18÷2) molecules of Acetyl-coA would be produced.

b. 2×8= 16 reduced nucleotides would be produced.

5. Energy yield of Beta oxidation

1 NADH = 2.5 ATPs = 2.5×8= 20ATP

1 FADH₂ = 1.5 ATPs = 1.5×8=12ATP

1 Acetyl-coA =10ATPs = 10×9= 90ATP

2 ATP used during oxidation.

TOTAL (Net) 120 ATPs will produced by oxidation of one molecule of Stearic acid.

Glucose produces net 32 ATP.

So One molecule of Stearic acid will produce more energy than one molecule of glucose.