Final answer:
Mitochondria are the organelles that produce large quantities of ATP molecules when both glucose and oxygen are available to the cell. They are often referred to as the "powerhouses" of the cell, responsible for generating ATP, the cell's main energy-carrying molecule.
Step-by-step explanation:
Mitochondria are the organelles that produce large quantities of ATP molecules when both glucose and oxygen are available to the cell. Mitochondria are often referred to as the "powerhouses" of the cell because they are responsible for generating ATP, which is the cell's main energy-carrying molecule. Muscle cells, in particular, have a high concentration of mitochondria because they require a lot of energy to contract.