• Before duplication, hydrogen bonds between bases are broken → double strands unwind and separate into single strands → each strand serves as a template for new, complementary strand → replicated DNA consists of a single strand of old DNA (template strand) and a single strand of new replicated DNA (complementary strand)                                                                 
  • This ensures that the DNA replication is identical.
  • A new DNA strand is the product of both continuous and discontinuous synthesis bcuz DNA synthesis only occurs in a 5′ to 3′ direction → synthesis of a DNA strand in a replication bubble is continuous at one replication fork and discontinuous at the other replication fork

The Elegant Experiment

After two rounds of semi-conservative replication, half the double helices will be half 15N and half 14N while the other helices will be all 14N