Final answer:
When fats are utilized for energy, the glycerol portion becomes DHAP and enters glycolysis to contribute to energy production.
Step-by-step explanation:
When fats are used as an energy source, the glycerol portion enters glycolysis when it has been converted to dihydroxyacetone phosphate (DHAP). After the process of lipolysis, glycerol is converted to glycerol-3-phosphate, and soon after to DHAP. DHAP is an intermediate in the glycolysis pathway, which can be further metabolized to produce energy. Fatty acids released from triglycerides undergo beta-oxidation to form acetyl CoA, which then enters the citric acid cycle. Notably, fats provide a significant amount of energy, often more than carbohydrates, when glucose levels are low. This is crucial for ATP generation during extended periods of fasting or vigorous exercise.