We humans have been looking for the fountain of youth as long as, well, pretty much as long as recorded history -- and we were probably seeking a way to skirt aging and death long before that. Whether it's some sort of special water, plastic surgery or another flavor of anti-aging remedy, the fountain of youth has forever eluded us. Our skin sags. Our minds grow forgetful. Our bodies begin to deteriorate. This is the natural degeneration process, and it's not skin deep; it's DNA deep.

Our chromosomes are like threads, but instead of being made up of strands of fiber, they're packed full of protein and tight coils of DNA. This DNA determines everything from the color of our eyes to whether we'll have conditions such as Down syndrome, sickle cell disease or cystic fibrosis. With the exception of our reproductive cells, all cells in the human body contain a complete copy of our DNA.

The cells that make up our bodies are constantly dividing, replicating in order to keep our bodies running with new, healthy cells that function properly -- cell division is important for making blood, bones and skin. This process is important because when our cells don't properly and exactly copy themselves, the abnormal cells may cause cancer or other conditions. The work of copying cells and cell division falls to enzymes known as polymerases.

Polymerases control the replication of our DNA by making sure the DNA threads end up as exact copies from one end to the other.

The tips of our chromosomes are a different matter. The ends of our chromosomes are made up of cells with a DNA sequence that protects the threads of DNA from unraveling, a natural fraying effect that is part of cell division. These ends are called telomeres.

Here's what's interesting about telomeres: They lengthen and shorten, and as our cells age -- as we age -- they grow shorter. Or, is it that as they shorten, we age? Could telomeres be the key to slowing down or stopping the aging process? Let's find out more about the link between telomeres and aging, next.