Skip to main content
Ch.18 Metabolic Pathways and ATP Production
Timberlake - Chemistry: An Introduction to General, Organic, and Biological Chemistry 14th Edition
Timberlake14th EditionChemistry: An Introduction to General, Organic, and Biological ChemistryISBN: 9781292472249Not the one you use?Change textbook
All textbooksTimberlake 14th EditionCh.18 Metabolic Pathways and ATP ProductionProblem 98a
Chapter 18, Problem 98a

Which of the following molecules will produce the most ATP per mole?
a. glucose or stearic acid (C18)

Verified step by step guidance
1
Understand the context: ATP (adenosine triphosphate) is the primary energy currency in cells. The amount of ATP produced depends on the molecule's structure and the number of carbon atoms it contains. Glucose and stearic acid are metabolized differently, with stearic acid being a fatty acid and glucose being a carbohydrate.
Recall the metabolic pathways: Glucose undergoes glycolysis, the citric acid cycle (Krebs cycle), and oxidative phosphorylation. Stearic acid undergoes beta-oxidation, the citric acid cycle, and oxidative phosphorylation. Fatty acids like stearic acid generally yield more ATP because they have more carbon atoms and are more reduced than glucose.
Compare the number of carbons: Glucose (C₆H₁₂O₆) has 6 carbon atoms, while stearic acid (C₁₈H₃₆O₂) has 18 carbon atoms. More carbon atoms mean more acetyl-CoA molecules can be produced during metabolism, leading to more ATP generation.
Analyze the ATP yield per molecule: Each glucose molecule produces 2 ATP from glycolysis, 2 ATP (or GTP) from the citric acid cycle, and approximately 28-30 ATP from oxidative phosphorylation, totaling around 32 ATP. In contrast, stearic acid produces significantly more ATP because each cycle of beta-oxidation generates NADH and FADH₂, which contribute to ATP production, and each acetyl-CoA enters the citric acid cycle.
Conclude: Since stearic acid has more carbon atoms and undergoes beta-oxidation, which is highly efficient in generating ATP, it will produce more ATP per mole compared to glucose.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
1m
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Cellular Respiration

Cellular respiration is the metabolic process by which cells convert nutrients into energy, specifically ATP. It involves glycolysis, the citric acid cycle, and oxidative phosphorylation. Different substrates, such as carbohydrates and fatty acids, yield varying amounts of ATP based on their chemical structure and the number of carbon-hydrogen bonds present.
Recommended video:
Guided course
1:47
Anaerobic Respiration Concept 1

ATP Yield from Glucose vs. Fatty Acids

Glucose typically yields about 30-32 ATP molecules per molecule during cellular respiration, while fatty acids, such as stearic acid (C₁₈), can produce significantly more ATP due to their higher number of carbon atoms. Each fatty acid undergoes beta-oxidation, generating multiple acetyl-CoA units that enter the citric acid cycle, leading to a greater ATP output compared to glucose.
Recommended video:
Guided course
2:48
Total Energy From Glucose Concept 2

Beta-Oxidation

Beta-oxidation is the metabolic process by which fatty acids are broken down in the mitochondria to generate acetyl-CoA, NADH, and FADH₂. This process is crucial for the energy yield from fatty acids, as each cycle of beta-oxidation shortens the fatty acid chain by two carbon atoms, allowing for multiple rounds of ATP production through subsequent metabolic pathways.
Recommended video:
Guided course
02:32
Characteristics of Beta Particles
Related Practice
Textbook Question

Which of the following molecules will produce the most ATP per mole?

d. glucose or caprylic acid (C8)

Textbook Question

Which of the following molecules will produce the most ATP per mole?

d. lauric acid (C12) or palmitic acid (C16)

Textbook Question

Which of the following molecules will produce the most ATP per mole?

a. glucose or maltose

Textbook Question

Identify each of the following reactions a to e in the β oxidation of palmitic acid, a C16 fatty acid, as

(1) activation

(2) first oxidation

(3) hydration

(4) second oxidation

(5) cleavage

c. Palmitic acid, CoA, and ATP form palmitoyl CoA.

Textbook Question

Which of the following molecules will produce the most ATP per mole?

c. two acetyl CoA or one palmitic acid (C16)