By Dr. Brian McDonough

By Dr. Brian McDonough, Medical Editor

PHILADELPHIA (CBS) – It remains one of the biggest questions for scientists – why do we age? Several reports in the journal Science look at very interesting theories.

The one that gets the most traction is the mitochondrion. Think back to high school. And think back to Biology class – a part of the cell called the mitochondria.

You may remember the mitochondria was called the power-pack of the cell, providing energy. Well it may have another function. It could help to cause a decline in muscle mass, hearing loss, and other aspects of aging.

It seems mitochondria has its own DNA that works differently than the DNA of the nucleus of the cell. And this mitochondrial DNA has more mutations than regular DNA.

As we age, the mutations in the mitochondria worsen. The result is seen as the changes associated with aging.

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