EINSTEIN & TIME

• Traveling at speed of light, time is relative

• Not only do you not age, but each moment of your existence, past, present and future exists forever

If cells can undergo mitotic division, replacing cells with new daughter cells,

why are our lifespans finite?

HeLa Cells

• “Immortal Cell Line”• Obtained from

Henrietta Lacks in 1951

• Used to develop polio vaccine and in almost all human studies

• Cells divide well past Hayflick Limit (50-75 times)

Why do cells stop dividing?

Three Models For Cellular Senescence

• Oxidative stress

• Effects of Prolonged Caloric Intake

• Telomere disintegration

Model 1: Oxidative Stress

• Free radicals (i.e. peroxides) cause damage to DNA

• Damaged DNA cannot be replicated or is replicated with mistakes

• Loss of DNA code = loss of cellular function

Combating Oxidative Stress

• Antioxidants surround and/or remove free radicals

• Examples: Fruit, Red Wine

Model 2: Caloric Intake

• As cells age, unused glucose combines with protein and iron to create a caramel-like substance that inhibits cell function

• Cells cannot divide

Combating Glycosylation

• Caloric Restriction• Studies show that

individuals who cut their caloric intake by 1/3rd may live 33% longer than individuals who do not

Model 3: Telomere Disintegration

HeLa & Telomerase

• HeLa cells retain active versions of telomerase longer than other cells

Progeria

• Telomerase may slow the loss of cellular function due to rapid aging caused by the genetic disease progeria

How Long?

• Some scientists suggest that the human body has the potential to live for 200-300 years with telomerase therapy

Is Telomerase the fountain of youth?

Cancer & Telomerase

• Telomerase may be the chemical signal that allows cells to avoid G0 and continue to divide

• As cells divide more rapidly, they rush through G1, G2 and S subphases

• Cells reproduce quickly but lose function due to loss of proper form