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● RNA being a biocatalyst is more reactive.
● DNA is double­stranded having complementary strand, which resists

the changes by repair mechanism.

DNA Replication with Experimental Proof Machinery and Enzymes
Involved
What is DNA Replication?

● DNA replication is the phenomenon in which a duplicate copy of DNA is

synthesised.
● In replication, two strands of the DNA helix separate and each strand

acts as a template for synthesising new complementary strands.
● After completion of replication, the two copies so produced will have
one parental and one newly synthesised strand. This scheme of

replication is called semi­conservative replication.

Experiment to Prove That DNA Replicates Semi­Conservatively

● Performed by − Messelson and Stahl

● E.coli​was grown in a medium containing heavy isotope ​N as the
15​
nitrogen source.
N was incorporated into newly synthesised DNA as well and the DNA
● 15​
became heavy DNA.