Cellular Aspects of Aging

There are five major theories of aging.

1. Cellular clock. A cell line may die out after a certain time or a certain number of cell divisions.

2. Death genes. There may be “death genes” which turn on late in life, causing cells to die.

3. DNA damage. Telomeres normally protect DNA from damage during replication, and telomerase protects telomeres. Aging cells lack telomerase and telomeres, and other DNA, become open to damage.

4. Free radicals. Free radicals may also damage DNA.

5. 5. Mitochondrial damage.

Mitochondrial DNA may be the most sensitive to free-radical damage. This may result in loss of proteins critical tomitochondrial function.

No functional mitochondria = no energy for cell