Q. 18.59 - An Introduction to General, Organic, and Biological Chemistry

Question

Consider the complete oxidation of oleic acid, ${\mathrm{CH}}_3-{\left({\mathrm{CH}}_2\right)}_7-\mathrm{CH}=\mathrm{CH}-{\left({\mathrm{CH}}_2\right)}_7-\mathrm{COOH}$, which is a ${\mathrm{C}}_{18}$ monounsaturated fatty acid.

a. How many cycles of  $\mathrm{\beta }$-oxidation are needed?

b. How many acetyl CoA are produced?

c. How many ATP are generated from the oxidation of oleic acid?

Step-by-Step Solution

Answer

(a) The eight cycles of $\mathrm{\beta }$-oxidation are needed

(b) The nine acetyl-CoA are produced

(c) The $146$ ATP is generated from the oxidation of oleic acid

Part (a) Step 1: Given information

We need to find the no. of cycles of $\mathrm{\beta }$-oxidation needed 

Part (a) Step 2: Explanation

Acetyl COA is formed when fatty acids are oxidized. Beta oxidation of fatty acids removes two carbons from the carboxylic end in stage two of fat metabolism. Each $\mathrm{\beta }$-oxidation produces acetyl-CoA and a two-carbon shorter fatty acid. $\mathrm{\beta }$-oxidation continues until acetyl-CoA is formed from the fatty acid.

To be entirely oxidized, oleic acid, a ${\mathrm{C}}_{18}$ monosaturated fatty acid, must go through eight $\mathrm{\beta }$-oxidation cycles.

Part (b) Step 1: Given information

We need to find the no. of acetyl CoA produced  

Part (b) Step 2: Explanation

Acetyl COA is formed when fatty acids are oxidized. $\mathrm{\beta }$ -oxidation of fatty acids removes two carbons from the carboxylic end in stage two of fat metabolism. Each $\mathrm{\beta }$-oxidation produces acetyl-CoA and a two-carbon shorter fatty acid. $\mathrm{\beta }$-oxidation continues until acetyl-CoA is formed from the fatty acid.

To be entirely oxidized, oleic acid, a ${\mathrm{C}}_{18}$ monosaturated fatty acid, must go through eight $\mathrm{\beta }$-oxidation cycles. As a result, nine acetyl-CoA are produced after eight $\mathrm{\beta }$-oxidation cycles.

Part (c) Step 1: Given information

We need to find the ATP generated from the oxidation of oleic acid

Part (c) Step 2: Explanation

One NADH, one ${\mathrm{FADH}}_2$ , and one acetyl-CoA are created in each $\mathrm{\beta }$-oxidation cycle. It's worth noting that NADH and ${\mathrm{FADH}}_2$ both produce three and two ATP, respectively. Furthermore, the activation of the fatty acid necessitates the use of two ATP molecules.

Oleic acid goes through eight $\mathrm{\beta }$-oxidation cycles, yielding nine acetyl-CoA.

Therefore, $146$ ATP are generated