• Question: Under what condition that the cell cannot read their manual ?

    Asked by amyhui to Jo, Loren, Lucy, Sam, Toby on 19 Jun 2014.
    • Photo: Jo Nettleship

      Jo Nettleship answered on 19 Jun 2014:

      For cells to live they have to be in the right conditions. For example, a human cell likes to be 37’C (body temperature) and we grow insect cells at 26’C as insects are cold blooded. If the cells are in the wrong conditions, too hot for example, then go into shock before dying. When they are in shock, they can turn off some genes and so do not act normally. This look like the cell is not reading the manual properly. If the temperature goes back to normal, and the cell isn’t dead, then it will recover and act normally again. Other conditions could be too much salt or not enough food.

    • Photo: Tobias Warnecke

      Tobias Warnecke answered on 19 Jun 2014:

      Hi amyhui,

      I thought I’d add a little bit about what happens when you don’t have the right conditions that Jo mentioned.

      Basically, the machinery that reads the manual likes running at its normal steady pace. When you stress the cell out (with heat or cold or by starving it – any way you can think of, really), you take that well-oiled machine out of its comfort zone. Like taking a racing bike, that works really well on a road, and riding it on a mountain bike trail.

      Sometimes, though, you don’t even need bad conditions to make a mistake. Sometimes, the manual is just very hard to read. For example, a sentence in the manual might read “GGGGGGGGGG” (10 Gs in a row). It’s not very easy for the decoding machine to keep track of where it got to so it might skip a G or two although it shouldn’t.

    • Photo: Sam Lear

      Sam Lear answered on 19 Jun 2014:

      Sometimes the manual is damaged as well.

      DNA can be damaged by lots of things – like UV light from the sun when you get sunburn for example. Your DNA reading machinery can generally cope with this, so it’s not usually a problem, but some things are worse, such as harmful radiation (produced inside nuclear reactors or by nuclear bombs) or certain harmful chemicals like mustard gas. These chemicals can cause mutations in DNA which can lead to cancer.

      Surprisingly some drugs used to treat cancer are actually designed to damage DNA – this is how they kill the cancer cells. These drugs can also be cancer causing as well however (if they cause unwanted DNA damage).

      Being a chemist, I occasionally have to use cancer-causing chemicals in the lab. I have to be very careful that I don’t expose myself to them though – as they might react with my DNA!

    • Photo: Loren Macdonald

      Loren Macdonald answered on 20 Jun 2014:

      Everyone else has already said so much so I’ll just add a little bit.

      Sometimes our cells can already have problems that mean that they find reading their manual, or their DNA, quite difficult. You require three main steps- reading the DNA and converting it to RNA (a similar language to DNA- like converting English to French), and then converting the RNA to the proteins (like turning the book into a movie) that make up most of the components of our cells. Things can go wrong at any of these steps- either through environmental damage (U.V light, radiation), natural errors or mutations (for example, cancer) or through inherited mutations (ones you get from your parents).

      It’s a complicated process, but our cells also have a lot of methods in place to make sure that these mistakes don’t happen and that we remain healthy. For example, damaged cells are often destroyed if they can’t be fixed.

    • Photo: Lucy Remnant

      Lucy Remnant answered on 20 Jun 2014:

      Sometimes if there is damage to the manual, or DNA, the cell can correct this.
      Lots of proteins work together to turn the DNA back to what it was before.

      If there is a problem in this repair, or with the proteins which ‘read’ the DNA then things can go wrong and we end up with diseases like cancer.