why is dna replication called semi-conservative
Ans :
Because each newly synthesized DNA molecule contains one original (parental) strand and one newly synthesized (daughter) strand, DNA replication is known as being “semi-conservative”. In their 1953 paper outlining the structure of DNA, James Watson and Francis Crick introduced this phrase.
The double-stranded DNA molecule unwinds during DNA replication, and each strand acts as a model for the synthesis of a new complementary strand. The procedure goes like this:
The complementary bases of the two DNA strands are exposed when they are split apart.
DNA polymerases are enzymes that add complementary nucleotides to each template strand while adhering to the A with T and C with G base-pairing rules.
As a result, two new DNA molecules are created, each of which contains one strand from the original DNA molecule and one that was recently synthesized strand.
The process is correctly referred to as “semi-conservative” because each new DNA molecule contains one strand from the original DNA and one newly synthesized strand. Each newly formed DNA molecule contains a portion of the original DNA molecule.
The other two proposed models of DNA replication were “dispersive” (where the DNA molecule is broken up into fragments and mixed with newly synthesized DNA fragments) and “conservative” (where the original DNA molecule is preserved in its entirety and a completely new DNA molecule is produced). The semi-conservative model put forth by Watson and Crick, however, was firmly supported by experimental data, including the well-known Meselson-Stahl experiment from 1958.