Question

In a chromosome, there is a specific DNA sequence, responsible for initiating replication. It is called as:

• A. Recognition sequence
• B. Cloning site
• C. Restriction site
• D. ori site

Answer 1

The Correct Option is D

The question asks us to identify the specific DNA sequence responsible for initiating replication in a chromosome.

Let's evaluate the options:

1. Recognition sequence: This term typically refers to the specific DNA sequences recognized by restriction enzymes, allowing these enzymes to cut DNA at precise locations. It does not initiate replication.
2. Cloning site: A cloning site is usually a region in a vector that contains multiple unique restriction sites where DNA fragments can be inserted during cloning experiments. It is not responsible for initiating replication.
3. Restriction site: A restriction site is a specific sequence of nucleotides where a restriction enzyme cuts the DNA. Similar to the recognition sequence, this does not serve the function of initiating DNA replication.
4. ori site: The “ori” or origin of replication is a specific DNA sequence where replication begins. This is crucial for the initiation of DNA replication, making it the correct choice for the question.

Conclusion: The correct answer is the ori site because it is the specific sequence necessary for the initiation of DNA replication in a chromosome. This site allows for the attachment of proteins that are essential for starting the replication process, ensuring that the DNA can be copied accurately for cell division.