A 62-year-old former professional football player is in the hospital for a total knee replacement as a result of wear and tear and a medical diagnosis of osteoarthritis. Which biological theory of aging would help explain this patient's current health problem?

Question

1. Cross-link
2. Free radical
3. Wear-and-tear
4. Somatic DNA damage

Answer 1

3. Wear-and-tear

Explanation: 1. The cross-link theory is related to the accumulation of cross-linked proteins causing disease. This theory does not explain the damage done to the patient's joint from playing football.
2. The free-radical theory states that cell damage is a result of accumulation of oxygen radicals. This theory does not explain the damage done to the patient's joint from playing football.
3. Osteoarthritis is characteristic of degeneration that results from joint usage. This disease is characteristic of the aspects of the wear-and-tear theory, which states that there is a "master clock" that controls all organs and cellular functions, which becomes less efficient over time. Abusing one organ or bodily system through repeated injury that occurs with contact sports may result in premature aging and diseases such as osteoarthritis.
4. The somatic DNA damage theory states that genetic mutations occur and accumulate with increasing age. This theory does not explain the damage done to the patient's joint from playing football.