• Question: Why do we die of old age?

    Asked by Sianna to Adrian, Gaia, Jim, Scott, Vicky on 10 Mar 2016.
    • Photo: Scott Lawrie

      Scott Lawrie answered on 10 Mar 2016:

      Cells in our bodies make copies of themselves, and they say every cell in your body gets replaced every seven years. So surely this could go on forever – why do we die?

      It’s because sometimes the copies aren’t perfect. Imagine photocopying a photograph, then copying that one, then copying that copy over and over again: the image on the copy would slowly get worse and worse (more blurry, less clear colours etc). The same thing happens to our cells. Sometimes they make mistakes when copying and you end up with a bad cell. This is cancer and that limits how much we can age 🙁

    • Photo: Gaia Andreoletti

      Gaia Andreoletti answered on 10 Mar 2016:

      Excellent question Sianna.
      There are two ideas regarding this questions:

      In the first, the idea is that our genes determine how long we live. We have a gene or some genes that tell our body how long it will live. If we were able to change that particular gene, we could live longer.

      The second idea is that over time, our body and our DNA get damaged until we can no longer function properly. The idea here is that how long we last is really just a consequence of small changes in our DNA. These changes add up until the total amount of damage is too much to bear and we die.

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