The process by which cells that were once mature and differentiated become undifferentiated and immature in appearance and behavior is known as

Anaplasia

Explanation:

Anaplasia refers to the loss of cell differentiation, which occurs when cells that were previously mature and differentiated become undifferentiated and immature in appearance and behavior. Anaplasia is a fundamental point for the emergence of malignant diseases. Anaplasia is characterized by:

Cellular Pleomorphism: variation of shape and size of cells and their nuclei. Hyperchromasia: very dark colored nuclei. Abundant Mitoses: Indicates Proliferative Activity Polarity Loss: Formation of tumor masses that grow in an unorganized manner.  Giant Tumor Cells: They have only one huge single polymorphic nucleus, with two or more nuclei. (Not to be confused with foreign body giant cells or inflammatory Langhans cells)

Mitochondria is the cell organelle that produced the energy that is needed in the body system in form of atp, that is why it is called the power house of the cell. energy is needed by the living organisms to carry out the activities which sustain life.  if the mitochondria is destroyed atp will not be produced. if the mitochondria is destroyed, energy production will stop and the affected living organism will not have the energy to carry out the necessary life processes; this will lead to the death of the organism.