Replication

All organisms carry the genetic code for their functions as a DNA molecule. Before a cell divides by mitosis, the DNA must undergo semi-conservative replication to produce two identical copies for the daughter cells. Enzymes play a key role here. Helicase binds to the DNA, breaking the hydrogen bonds that hold the two polynucleotide chains together. This reveals two template strands which have exposed bases which bind to DNA-nucleotides. A second enzyme, DNA polymerase then forms a phosphate-sugar backbone by joining adjacent nucleotides with a condensation reaction