What Is Cell Waste Disposal?

The cell is the most basic unit of life, but it engages in very complex behavior. The cell is constantly at work to maintain homeostasis. Homeostasis is essentially the cell trying to keep the conditions inside the same at all times. On occasion, this means that the cell needs to get rid of some of the waste products that it creates. The cell has many ways to dispose of cellular waste.

Definition of Cellular Waste

A living cell uses a number of different chemical reactions to survive. These processes create a large amount of waste that the cell needs to remove. This includes the byproducts of reactions designed to burn energy, as well as toxic metabolites such as reactive oxygen species. In addition, many of the parts of the cell break down over time and need to be eliminated.

Lysosomes

The major route of cellular waste disposal works through an organelle called a lysosome. This is a special pocket of the cell that has a number of different proteins, called enzymes, that are designed to break down cellular waste. Lysosomes can help break down parts of the cell that are worn out or get rid of waste products that are created by different parts of the cell.

Ubiquitin

In some cases, a protein begins to get bent out of shape, which can cause it to lose its function and clog up the cell. In this case, it is recognized by another protein, called a ubiquitin-ligase enzyme, which then attaches a small protein called ubiquitin to the damaged protein. Ubiquitin acts as a signal to the rest of the cell that this protein needs to be broken down, and it is often targeted by the lysosome or other digesting proteins so that the parts of the protein can be used again.

Scavengers

Another way in which a cell disposes of waste is through a series of compounds called scavengers. These are molecules that are present in the cell and can bind to toxic molecules and other substances that the cell doesn't want around anymore. For example, reactive oxygen species, which are toxic versions of oxygen that can damage the cell, are often eliminated through the use of antioxidants.

Secretion

In some cases, the cell may not have the time or the resources to get all of its waste out. In this case, the cell will often pump out its waste products through a process called exocytosis. Exocytosis is a way for the cell to get rid of large quantities of waste products all at once. For smaller amounts of waste products, the cell has specialized pumps that use energy to move the waste product out of the cell.