Question

In which type of DNA replication of the two newly formed molecules, one is purely a new one and the other one old?
A. Conservative
B. Semi Conservative
C. Dispersive
D. Both conservative and semi-conservative

Answer 1

Hint:
DNA that is semi-conservative replicates and uses each strand as a template for a new strand. In an experiment, radioactive nitrogen-14 and 15 were used to demonstrate it. The mechanism that generates new DNA strands and results in variations in organisms is crucial.

Complete answer:
Deoxyribonucleic acid, or DNA, is the genetic material that may be passed down from one generation to the next. The method by which duplicate DNA strands can be created is known as DNA replication. The semi-conservative technique of DNA describes how two initial DNA strands split during replication and how each strand acts as a template strand for creating new DNA strands. It happens in opposite directions. This produces two copies of the DNA molecule, which is why this process is known as semi-conservative replication. One newly synthesised strand and one other newly synthesised strand are present.
Nikolai Koltsov foresaw the semi-conservative DNA model. James D. Watson and Francis Crick conducted an experiment to demonstrate this structure in 1953. The experiment, which makes use of the radioactive isotopes nitrogen-15 and nitrogen-14, proved it. A hybrid of 14 and 15 was seen in the first observation, but in the second cycle, the hybrid is still there, along with light DNA. This demonstrates the DNA's somewhat conservative behaviour.
Hence, the correct option is Semi Conservative

Option ‘B’ is correct

Note:
DNA repair benefits from DNA replication that is semi-conservative. The new DNA strand has the ability to change itself. The double helix's two strands remain connected during conservative replication, creating a copy made up of two fresh strands. Two DNA copies containing different DNA regions can be created via disruptive replication. Either the original and additional strands are present.