Question

A multiple cloning site:

• A. Contains several copies of a cloned gene.
• B. Allows multiple choices for choosing organisms for cloning.
• C. Allows multiple choices for choosing restriction enzymes for cloning.
• D. Contains multiple copies of the same restriction enzyme.

Hint:

Break down the name: "Multiple Cloning Site". It's a single \textbf{site} for \textbf{cloning} that offers \textbf{multiple} options. The options are the different restriction enzyme recognition sequences it contains.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
A Multiple Cloning Site (MCS), also known as a polylinker, is a short segment of DNA which has been engineered into a cloning vector (like a plasmid). Its purpose is to provide convenience and flexibility for inserting a gene of interest into the vector.

Step 2: Detailed Explanation:
- The key feature of an MCS is that it contains recognition sequences for numerous different restriction enzymes, clustered together in one location.
- This design provides a researcher with a wide variety of choices for which enzyme(s) to use for cutting the plasmid and ligating the target DNA fragment. This allows for compatibility with whatever restriction sites are available on the ends of the DNA insert.
- Let's analyze the options:
- (A) is incorrect. The MCS is the site where a gene is cloned; it doesn't contain the gene initially.
- (B) is incorrect. The choice of organism is determined by other factors, not the MCS.
- (C) is correct. This is the primary function of the MCS – to offer a selection of unique restriction sites.
- (D) is incorrect. The MCS contains sites for many different enzymes, not multiple copies of the same one.

Step 3: Final Answer:
The function of a multiple cloning site is to allow multiple choices for choosing restriction enzymes for the cloning process. Therefore, option (C) is correct.