Final answer:
Mitophagy, involving lysosomes and proteasomes, is the mechanism by which cells degrade obsolete parts like defective mitochondria, ensuring cellular health through controlled degradation of damaged organelles and proteins.
Step-by-step explanation:
The mechanism used for degrading obsolete parts of a cell, such as a defective mitochondrion, is called mitophagy, which is a specific form of autophagy. Mitophagy leads to the destruction of mitochondria, ensuring that damaged or unnecessary mitochondria are removed from the cell.
This process is crucial for maintaining cellular health and efficiency. The cell's lysosomes are central to this process, as they contain hydrolytic enzymes that break down the defective organelle once it is delivered to the lysosome
It's worth noting that there are regulatory controls at the cellular level that may govern the replication and segregation of mitochondrial DNA by the nucleus, as it relates to homeostasis and selection within the organelle and the organism as a whole. In addition, proteasomes also play a role in protein turnover and degradation, where ubiquitin tags unwanted proteins for destruction within the proteasome complex.