Q. 18.60 - An Introduction to General, Organic, and Biological Chemistry

Question

Consider the complete oxidation of palmitoleic acid, ${\mathrm{CH}}_3-\left({\mathrm{CH}}_2\right)-\mathrm{CH}=\mathrm{CH}-{\left({\mathrm{CH}}_2\right)}_7-\mathrm{COOH}$, which is a ${\mathrm{C}}_{16}$ monounsaturated fatty acid found in animal and vegetable oils.

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 palmitoleic acid?

Step-by-Step Solution

Answer

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

(b) The eighth acetyl-CoA are produced

(c) The $129$ ATP is generated from the oxidation of palmitoleic 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. B-oxidation continues until acetyl-CoA is formed from the fatty acid.

To be entirely oxidized, palmitoleic acid, a ${\mathrm{C}}_{16}$ monosaturated fatty acid, must go through seven $\mathrm{\beta }$-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. B oxidation of fatty acids removes two carbons from the carboxylic end of the fatty acid during stage two of fat metabolism. As a result, every $\mathrm{\beta }$-oxidation produces acetyl-CoA and a two-carbon shorter fatty acid. The fatty acid is metabolized to acetyl-CoA by $\mathrm{\beta }$-oxidation.

To be entirely oxidized, palmitoleic acid, a ${\mathrm{C}}_{16}$ monosaturated fatty acid, must undergo seven $\mathrm{\beta }$-oxidation cycles. As a result, eight acetyl groups were produced after seven $\mathrm{\beta }$-oxidation cycles.

Part (c) Step 1: Given information

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

Part (c) Step 2: Explanation

NADH, ${\mathrm{FADH}}_2$, and acetyl-CoA are created in each $\mathrm{\beta }$-oxidation cycle. Note that NADH and ${\mathrm{FADH}}_2$ each produce three and two ATP. Furthermore, two ATP are required for fatty acid activation.

Therefore, $129$ ATP are generated