Read Replication by Model, Direction and Substrate
Replication is template-directed DNA synthesis; isotope patterns test its model, and nucleotide chemistry supplies both substrate and energy.
DNA Replication is the central idea in this question pattern. Identify the condition in the stem before applying the method below.
Read density outcomes
Semiconservative replication gives daughter duplexes with one old and one new strand after the first generation. Conservative replication retains the original heavy duplex and creates a fully light duplex; after two generations this can yield 25% heavy and 75% light DNA.
Add the next nucleotide
DNA polymerase incorporates an incoming dNTP as a dNMP at the growing 3′-OH end, releasing pyrophosphate. Taylor’s Vicia faba autoradiography also supported semiconservative chromosome replication.
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- ✓Semiconservative: each daughter duplex has one parental strand.
- ✓dNTP → incorporated dNMP + pyrophosphate.
- ✓DNA extends 5′→3′ at a free 3′-OH.
Do not confuse the growing 3′ end with the direction in which the new strand is written.
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