Answer:
In the semi-conservative method of DNA replication, each of the strands of the double helix acts as a template for replication.
Step-by-step explanation:
Semi-conservative DNA Replication:
- Semi-conservative DNA replication produces two daughter helices from the original parent helix. One strand of the daughter helix is form the original template while the other is newly synthesized.
- This means that one strand will have the base sequence identical to the parent, while the other will be complementary to the template.
- This model was experimentally confirmed by an experiment conducted in 1958 by Meselson and Stahl. They used radioactive isotope of nitrogen i.e. N-14 or N-15. DNA molecules made with N-15 were allowed to replicate in the presence of N-14.
- After first replication, DNA molecules contained both N-15 and N-14 isotopes, disproving the conservative model that stated that the new helices are completely identical to the template.
- The second replication yielded only N-14 which disproved the dispersive model that the new helices are a combination of both the template and new strands.
* The attached image compares the three proposed models for DNA replication.