one upon a time a DNA segment became damaged.
that shouldn't be there right?
DNA glycosylase saw this and thought he could help!
so he attached himself to the damaged DNA.
he removed (excised) the damaged base.
but this wasn't enough!
now there's a gap.
AP endonuclease thought she could fill the gap.
so she took away the piece of the backbone and sat in the space.
somthing still wasn't right!
DNA polymerase and DNA ligase came along to try help out thhis injured piece of DNA.
DNA polymerase put the right base in the gap.
DNA ligase sealed the base in.
the DNA segment lives happily ever after...