Final answer:
Glucose, pyruvate, and fatty acids are all direct sources of fuel for mitochondria. Therefore, there is no correct answer among the options given as all are utilized by mitochondria to generate energy.
Step-by-step explanation:
The fuel sources for mitochondria include glucose, pyruvate, and fatty acids. Glucose is the primary energy source utilized by cells through glycolysis and the subsequent Krebs cycle. Pyruvate is the product of glycolysis and is converted into acetyl CoA before entering the Krebs cycle. Fatty acids undergo β-oxidation to form acetyl CoA, which also enters the Krebs cycle.
To directly answer your question, all three options listed, A. Glucose, B. Pyruvate, and C. Fatty Acids are direct sources of fuel for mitochondria. Therefore, none of the options provided should be considered as not a direct source of fuel for mitochondria.
In reference to the related questions:
- During the catabolism of glucose, FADH2 is produced only in the Krebs cycle.
- Pyruvate is not a commercially important fermentation product.
- A lack of Krebs cycle enzymes would prevent a cell from processing acetyl CoA to CO₂.
- The citric acid cycle (Krebs cycle) follows glycolysis.
- The outer membrane of a eukaryotic cell is not likely derived from an endosymbiotic bacterium.