Select at least 3 biological theories of aging from your textbook.

1. In the text, we discuss three theories about aging.

• The Theory of Wear and Tear
• Free Radical Theory
• Theory of Cross-Linkage

2. Each theory is explained as follows

• This theory states that over time, your body will wear out due to the damage accumulated from exposure to toxins and daily usage. The damage is visible in wrinkles, grey hair and diseases associated with ageing such as osteoarthritis. Essentially, the body’s cells and tissues are unable to keep up with the constant repair and regeneration needed to maintain optimal function.
• Free Radical Theory: The theory states that the accumulation in the body of free radicals is the cause of aging. Free radicals can cause cell death and dysfunction by damaging DNA and proteins. Over time, the accumulation of free radicals can contribute to the development of age-related diseases such as cancer, Alzheimer’s disease, and cardiovascular disease.
• Cross-Linkage Theory: This theory suggests that aging is caused by the accumulation of cross-linked proteins in the body’s tissues. The process of glycation, which involves the binding of glucose molecule to protein results in cross-linking. It can cause the protein to become stiffer and less elastic. This leads to tissue dysfunction and damage. It has been shown that cross-linking is linked with diseases associated with aging, such as atherosclerosis and diabetes.

In general, the theories indicate that aging involves a number of factors. Each theory is flawed in some way, but they highlight that maintaining optimal tissue and cellular function over the course of a lifetime promotes healthy aging.