Question 1

Which of the following best explains why fatty acids are considered a major source of stored metabolic energy in humans?

Accepted Answer

Fatty acids are highly reduced molecules, yielding more ATP per carbon than carbohydrates.

Question 2

During fasting, which hormone stimulates the release of fatty acids from adipose tissue, and what is the immediate product of this process?

Accepted Answer

Glucagon; free fatty acids and glycerol

Question 3

Which enzyme catalyzes the rate-limiting step in the mobilization of stored triacylglycerols in adipose tissue?

Accepted Answer

Hormone-sensitive lipase

Question 4

After lipolysis in adipose tissue, how are fatty acids transported in the blood to tissues that require energy?

Accepted Answer

Bound to serum albumin

Question 5

Which of the following correctly describes the activation of a fatty acid prior to mitochondrial transport?

Accepted Answer

Fatty acid + ATP + CoA $$\rightarrow$$ fatty acyl-CoA + AMP + PP$$_i$$

Question 6

What is the primary role of carnitine in fatty acid metabolism?

Accepted Answer

It shuttles long-chain fatty acyl groups across the inner mitochondrial membrane.

Question 7

Which of the following best describes the fate of glycerol released from adipose tissue during lipolysis?

Accepted Answer

It is converted to glucose in the liver via gluconeogenesis.

Question 8

Which enzyme catalyzes the first step of β-oxidation of fatty acids in the mitochondrial matrix?

Accepted Answer

Fatty acyl-CoA dehydrogenase

Question 9

During β-oxidation, which coenzymes are reduced, and what is their fate?

Accepted Answer

NAD^+ and FAD are reduced to NADH and FADH$$_2$$, which donate electrons to the electron transport chain.

Question 10

How many cycles of β-oxidation are required to completely oxidize palmitoyl-CoA (C$$_{16}$$:0) to acetyl-CoA?

Accepted Answer

7

Question 11

Calculate the net ATP yield from the complete oxidation of one molecule of palmitate (C$$_{16}$$:0), considering the activation cost.

Accepted Answer

$$106$$

Question 12

Which of the following statements about chylomicrons is correct?

Accepted Answer

They transport dietary triacylglycerols from the intestine to tissues via the lymph and blood.

Question 13

Which of the following best explains why the β-oxidation of fatty acids produces more ATP per carbon than glucose oxidation?

Accepted Answer

Fatty acids are more reduced, allowing more electrons to be transferred to NAD^+ and FAD.

Question 14

Which of the following is the correct sequence of reactions in one cycle of β-oxidation?

Accepted Answer

Oxidation, hydration, oxidation, thiolysis

Question 15

A patient with a deficiency in carnitine acyltransferase I would most likely experience which of the following symptoms during fasting?

Accepted Answer

Reduced ability to oxidize long-chain fatty acids

Question 16

Which of the following best describes the role of thiolase in β-oxidation?

Accepted Answer

It cleaves the β-ketoacyl-CoA, releasing acetyl-CoA and a shortened acyl-CoA.

Question 17

Which of the following equations correctly represents the activation of palmitate for β-oxidation?

Accepted Answer

$$\mathrm{Palmitate} + \mathrm{ATP} + \mathrm{CoA} ightarrow \mathrm{Palmitoyl	ext{-}CoA} + \mathrm{AMP} + \mathrm{PP}_i$$

Question 18

Which of the following is a direct product of the first oxidation step in β-oxidation?

Accepted Answer

Trans-Δ$$^2-$$enoyl-CoA

Question 19

If a mutation impairs the function of acyl-CoA dehydrogenase, what is the most immediate metabolic consequence?

Accepted Answer

Accumulation of fatty acyl-CoA and decreased FADH$$_2$$ production

Fatty Acid Catabolism: Mechanisms and Energetics

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