Final answer:
In eukaryotes, the remaining energy in pyruvate is extracted in the mitochondria, which are responsible for producing ATP, the cell's main energy-carrying molecule.
Step-by-step explanation:
In eukaryotes, the remaining energy in pyruvate after glycolysis is extracted in an organelle known as the mitochondria. These organelles are often referred to as the power plants of the cell because they produce adenosine triphosphate (ATP), the primary energy carrier molecule that cells use for their metabolic activities. During cellular respiration, pyruvate molecules produced in glycolysis enter the mitochondria where they are further processed in the Krebs cycle and the electron transport chain to produce ATP.