Question

Which of the following methods/tools is not used for introduction of recombinant DNA into host cell?

• A. Microinjection
• B. Denaturation
• C. Gene gun
• D. Heat shock method

Hint:

Remember that gene transfer methods are about getting DNA {across the cell membrane}. Microinjection, gene gun, and heat shock are all ways to achieve this. Denaturation is about changing the DNA's shape from double-stranded to single-stranded.

Answer 1

The Correct Option is B

Step 1: Concept Overview:
The question requires identifying the option that is NOT a method for transferring foreign DNA into a host cell, a process also known as transformation or transfection.
Step 2: Detailed Analysis:
Analyzing each option:
Microinjection: A physical method involving the direct injection of a DNA solution into a cell's nucleus using a fine glass needle. A common technique.
Denaturation: The separation of DNA strands in a double helix, usually via heat or chemicals. While crucial in PCR and Southern blotting, it does NOT introduce DNA into cells.
Gene gun (Biolistics): A physical method that uses microscopic gold or tungsten particles coated with DNA, which are propelled into cells to deliver the DNA. Commonly used, especially for plant cells.
Heat shock method: A chemical method, mainly for bacterial transformation. Cells are treated with calcium chloride (\(CaCl_2\)) to make them "competent," followed by a rapid temperature increase (heat shock) to temporarily allow DNA plasmids to enter the cell. It is a standard method.
Step 3: Conclusion:
Denaturation modifies DNA structure but does not introduce DNA into a host cell.