And the cytosol contains these free ribosomes that basically move about this entire fluid region. Now let's move on to the mitochondria. The mitochondria is a very important structure in the eukaryotic cell. The mitochondria, in a way, is like the nuclear power plant because it transforms one type of energy into a different type of energy that the cell can then use to help power different types of processes. So the mitochondria is the power plant of the cell. It breaks down molecules, biomolecules and produces energies that can be harvested to power many different processes.