Final answer:
Glycerol is the only substrate among the given options that can be used for anaerobic energy production. It can enter glycolysis after being converted to glycerol-3-phosphate. Fatty acids require oxygen for their catabolism and cannot serve as an anaerobic energy source.
Step-by-step explanation:
Cellular Energy from Anaerobic Sources
When discussing the derivation of cellular energy anaerobically, we must consider glycolysis as the metabolic pathway capable of generating ATP in the absence of oxygen. In the options provided, the only potential anaerobic energy source is glycerol. Fatty acids, whether saturated or unsaturated and regardless of chain length, cannot be directly used for anaerobic energy production because their catabolism via beta-oxidation requires the mitochondria and oxygen. Therefore, the correct choice is d. glycerol, which can be converted to glycerol-3-phosphate and enter the glycolysis pathway.
While the conversion of fatty acids such as a 10-carbon saturated fatty acid, a 7-carbon unsaturated fatty acid, or a 12-carbon saturated fatty acid to acetyl-CoA is an important part of cellular respiration, these processes require oxygen for further energy production in the citric acid cycle and electron transport chain. Glycerol, as part of triglycerides, can be used in glycolysis, which does not require oxygen, making it the correct choice for anaerobic metabolism.