Repairing the damage

With so much DNA damage going on each day, cells need to be able to repair the harm.

DNA can get damaged in different ways and at different times. Cells have different ways of fixing DNA depending on what sort of damage is done and whether the cell is dividing when the damage is discovered.

First lets develop a clear picture of DNA. Let’s think of DNA as a chain with objects hanging off it like a charm bracelet.


In this case there are five pieces: hooks, eyes, locks, keys and the chain. In a cell the DNA pairs up with another strand – the hooks interlocking with eyes and the keys fitting into the locks.

When the chains pair-up, key goes with lock; hook with eye.

Each object fits nicely with an opposite object. So, when two chains come together they must have the matching sequence of objects in order to fit together.

The DNA code works in sets of three. For example, hook, hook, key might be the code for ‘E’. In addition there are sets of three that code for ‘start here’ and sets that code for ‘stop here’.  Follow the links to find out more about DNA coding and about the methods cells use to repair damage.  We will explore five different repair methods:


Fixing a damaged letter;

Short patch repairs;

Long patch repairs;

Template repairs;

End joiing repairs.