ZOOHCC - 501: Molecular Biology (Theory)
Unit 2: DNA Replication
The three models for DNA replication :-
Conservative
In the process, DNA self-replicates to create multiple copies. In conservative replication, two DNA copies are created from the original DNA, which serves as a template. Of these two, one is brand new DNA and the other is the old DNA strand. This type of DNA replication is biologically irrelevant.
Semi-Conservative
DNA replication is semi-conservative because the resulting DNA helix is composed of both new and old strands in the replication process. This is caused by complementary base pairs. That is, each nitrogenous base pairs only with its complementary pair. These two strands are identical to the first double helix. Each strand becomes a template for synthesizing new strands. - DNA replication is the process of replicating DNA. - The 1958 Meselson-Stahl experiment confirmed that DNA replication is semi-conservative. - In the semi-conservative DNA model, each DNA strand acts as a template to generate a new complementary strand, resulting in two DNA molecules with an old strand and a new strand. -His three different models have been proposed for DNA replication, but the semi-conservative model was the most popular among scientists at the time. His two other models were called conservative and decentralized.
Dispersive replication
Dispersive replication. In the dispersal model, DNA replication produces her two DNA molecules, which are mixtures or "hybrids" of parent and daughter DNA. In this model, each individual strand is a patchwork of original and new DNA.
The difference between conservative and semi conservative dna replication
| No | Conservative | Semiconservative Replication | ||||
|---|---|---|---|---|---|---|
| 1 |
Conservative replication is one of the three types of DNA replication. |
Semiconservative replication is the DNA replication mode proposed by Watson and Crick in 1953. |
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| 2 | One helix is entirely carried new DNA while the other helix carries entirely old DNA. | Each newly formed double helix contains one new and one old strand. | ||||
| 3 |
Not found to be biologically significant. |
Biologically significant | ||||
| 4 | DNA doesn't split open at all. |
DNA unwinds and opens for DNA replication. |
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| 5 |
Not clear |
Each strand in the DNA double helix acts as a template for the synthesis of a new. complementary strand. |
