Class 12 Biology Molecular Basis of Inheritance DNA Replication

DNA Replication

Replication is the process of reproducing or creating a copy of something. In this topic, we will see how DNA creates a copy of itself.

Various hypotheses were proposed by various scientists regarding the replication model of DNA i.e. how DNA replicates. Some of these were:

  • Semi-conservative DNA replication model
  • Conservative DNA replication
  • Dispersive DNA replication


Semi-conservative DNA replication model

Watson & Crick suggested the ‘Semi conservative DNA replication’ model. According to this model, the two strands of DNA separate.

Each strand act as template for synthesis of a new strand. The new strand is synthesized based on complementary base pairing with the template.

Each new DNA molecule has 1 parental strand & 1 one newly formed strand. This is how the original DNA molecule (1 copy) gives rise to two copies.


Conservative DNA replication

According to this model, Complete DNA molecule (and not just one strand) acts as a template for new synthesis.


Dispersive DNA replication

According to the Dispersive model, the new DNA is synthesized in short pieces. A part of the old strand is attached to the end of a part of newly synthesized strand.


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