Picture from: SPL
DNA replication. Coloured Transmission Electron Micrograph (TEM) of human DNA from a HeLa cancer cell, showing a stage of DNA replication. The strand of DNA is coloured yellow. It has formed into a Y-shaped molecule termed a replication fork, where the DNA has unwound into two single strands. Normally, DNA consists of two tightly wound spiral strands. During replication, a "bubble" region forms which enlarges to form a replication fork. It is here that daughter strands form as the parent DNA acts as a template for the construction of a new matching strand. In this way the sequence of bases (or genetic nformation) along the DNA molecule is replicated.