Question

1. dna molecules can be tens of thousands of base pairs in length. mistakes in dna replication lead to mutations, which may or may not be harmful to an organism. how does semi - conservative replication help prevent mutations during dna replication?

Explanation:

Semi - conservative replication means that each new DNA molecule has one old (template) strand and one new strand. The old strand can serve as a reference. DNA polymerases can proof - read the new strand against the old (template) strand. If there is a wrong base added during replication (a potential mutation), the DNA polymerase can detect the mismatch (due to the base - pairing rules, e.g., A should pair with T, C with G) because of the reference from the old strand. Then, the DNA polymerase can correct the error (by removing the incorrect nucleotide and adding the correct one).

Answer:

Semi - conservative replication provides a template (the old strand) for DNA polymerase to proof - read the newly synthesized strand. DNA polymerase can detect base - pairing mismatches (due to the template) and correct errors, thus helping prevent mutations.