Question

What does semiconservative mean in the context of DNA?

Answer 1

Semi conservative literally means "Half conserved".
In case of DNA , it is used for DNA replication in which one strand of DNA is conserved while other is not. Also primary structure of DNA duplex is conserved but secondary structure is disrupted.

Explanation:

Proper definition of Semi-Conservative model:
"The replication in which one strand of DNA is conserved and the other is synthesized according to complementary base pairing is called semi-conservative replication"
This model was suggested by Watson-Crick.
Short summary of this model is given below:

• First of all, unzipping of double-stranded DNA takes place and the strands are separated.
• Each strand act as a template or mold and each strand gets its complementary nucleotides.
• New nucleotides are arranged on each model strand. Thus two daughter DNAs are formed.
• Each daughter DNA has one old(parental) strand and one newly formed strand.
• Thus the sequence of original duplex is conserved in the two daughter DNAs but the duplex itself is not conserved.

Thus the primary structure is conserved but the secondary structure is disrupted. This is known as semi-conservative `DNA` replication.

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Hope it helps...