Question 1

Which enzyme is required to move the double bond during the oxidation of unsaturated fatty acids when the double bond is not in the correct position?

Accepted Answer

Isomerase

Question 2

Why does the oxidation of a portion of an unsaturated fatty acid not generate FADH$_2$?

Accepted Answer

Because the double bond is already present and does not require dehydrogenation

Question 3

During the oxidation of odd-numbered fatty acids, what are the final products after the last round of $eta$-oxidation?

Accepted Answer

Acetyl-CoA and propionyl-CoA

Question 4

Which cofactor is used to reduce a double bond if isomerase cannot rearrange it during fatty acid oxidation?

Accepted Answer

NADPH

Question 5

Calculate the total ATP yield from the complete oxidation of palmitic acid (C$_{16}$:0), given the following yields per cycle: FADH$_2$: 1.5 ATP, NADH: 2.5 ATP, and the citric acid cycle yields 10 ATP per acetyl-CoA. Palmitic acid undergoes 7 cycles of $eta$-oxidation.

Accepted Answer

$106$ ATP

Question 6

Which of the following statements about the oxidation of odd-numbered fatty acids is correct?

Accepted Answer

Odd-numbered fatty acids produce propionyl-CoA, which is converted to succinyl-CoA and enters the citric acid cycle.

Question 7

If a fatty acid contains multiple points of unsaturation, which enzyme may be required for rearrangement during oxidation?

Accepted Answer

Isomerase

Question 8

What is the role of NADPH in the oxidation of unsaturated fatty acids?

Accepted Answer

It is used to reduce a double bond that cannot be rearranged by isomerase.

Question 9

Which of the following is NOT a product of one cycle of $eta$-oxidation of a saturated fatty acid?

Accepted Answer

ATP

Question 10

During fatty acid oxidation, which step directly produces FADH$_2$?

Accepted Answer

The dehydrogenation of acyl-CoA to trans-$	riangle^2$-enoyl-CoA

Question 11

Which cycle is responsible for the further oxidation of acetyl-CoA produced from fatty acid oxidation?

Accepted Answer

Citric acid cycle

Question 12

A patient has a deficiency in isomerase required for fatty acid oxidation. What is the most likely consequence?

Accepted Answer

Accumulation of unsaturated fatty acids with double bonds in the wrong position

Question 13

Which of the following best explains why ATP is not a direct product of $eta$-oxidation?

Accepted Answer

ATP is only produced during the citric acid cycle and oxidative phosphorylation, not during $eta$-oxidation.

Question 14

How many cycles of $eta$-oxidation are required to completely oxidize palmitic acid (C$_{16}$:0)?

Accepted Answer

$7$ cycles

Question 15

Which molecule is produced from propionyl-CoA before it enters the citric acid cycle?

Accepted Answer

Succinyl-CoA

Question 16

Which of the following is a common misconception about the oxidation of unsaturated fatty acids?

Accepted Answer

FADH$_2$ is always produced during the oxidation of every fatty acid.

Question 17

Which step in fatty acid oxidation is most affected by the presence of multiple points of unsaturation?

Accepted Answer

Isomerization and reduction of double bonds

Question 18

A mutation prevents the conversion of propionyl-CoA to succinyl-CoA. Which metabolic pathway would be directly affected?

Accepted Answer

Citric acid cycle

Question 19

Which of the following is a direct product of the citric acid cycle from acetyl-CoA generated by fatty acid oxidation?

Accepted Answer

NADH

Question 20

In the context of fatty acid oxidation, what is the significance of the equation $	ext{Palmitic acid} + 7 	ext{ cycles of } \beta	ext{-oxidation} ightarrow 8 	ext{ acetyl-CoA} + 7 	ext{ FADH}_2 + 7 	ext{ NADH}$?

Accepted Answer

It shows the stoichiometry of products generated from complete oxidation of palmitic acid.

Fatty Acid Oxidation: Mechanisms and Energetics

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