Beginning of Essay
The aging process is difficult to analyze because of the way that the body’s organ systems work together. The breakdown of one structure will ultimately affect the function of others. The medical field of gerontology deals with examining the biological changes ....

Middle of Essay
.... known as lipofuscin accumulates. As this happens, the mitochondria, or the “powerhouse of the cell” begins to break down, thereby decreasing the amount of energy that is being supplied to the cell. This cellular degeneration may be set into action by highly reactive chemicals known as free radicals. These molecules have an unpaired electron in the outermost valence shell. This causes the molecule to grab electrons from other molecules, setting into motion a chain reaction that destabilizes them, and causes death of the cell. These free radicals are the normal by-product of metabolism, and can also form due to exposure to radiation or tox ....