Question

ASSERTION : A piece of DNA inserted into an alien organism generally does not replicate if not inserted into a chromosome.
REASON : Chromosomes have specific sequences called ‘ori’ regions where DNA replication is initiated.
A) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B) Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
C) Assertion is correct but Reason is incorrect
D) Both Assertion and Reason are incorrect

Answer 1

A double helix with two complementary strands makes up DNA. These strands are separated throughout replication. Each strand of the initial DNA molecule then acts as a template, a method known as semi-conservative replication, for the creation of its counterpart.

Complete answer:
First we should know about DNA replication to answer this question. The biological method of creating two exact replicas of DNA from one initial DNA molecule is DNA replication. In all living organisms, DNA replication takes place, serving as the most important component of biological inheritance. The cell possesses a recognizable division property, which allows DNA replication necessary.
Now, let us find the solution from the options-
- 'Origin of replication' is a series from which polymerase enzyme binding begins with replication.
-During nuclear divides, an individual piece of DNA without replication root or 'ori' site cannot reproduce and is eventually destroyed.
-Although once it is placed into a chromosome, as a part of the replication mechanism started by the 'origin of replication' site of the chromosome, it is repeated together with the chromosome.
- It is why recombinant vectors used during genetic engineering must include the origin of replication in order to make sure the presence of the transgenic gene in all progeny, so that they might multiply during cell division.

Thus, the correct answer is option (B) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.

Note: It is also possible to conduct DNA replication in vitro (artificially, outside a cell). DNA polymerases extracted from cells and artificial DNA primers could be used in a template DNA sequence to initiate DNA synthesis at target sequence.