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: Understanding the Concept:
The question asks to identify which option is not a method for transferring foreign DNA into a host cell, a process known as transformation or transfection.
Step 2: Detailed Explanation:
Let's analyze the given options:
Microinjection: This is a physical method where a very fine glass needle is used to directly inject a DNA solution into the nucleus of a single cell. It is a commonly used method.
Denaturation: This is the process of separating the two strands of a DNA double helix, typically by applying heat or chemicals. It is a crucial step in techniques like PCR and Southern blotting, but it is not a method for introducing DNA into a cell.
Gene gun (Biolistics): This is a physical method where microscopic particles of gold or tungsten are coated with DNA and then shot at high velocity into target cells, penetrating the cell wall and membrane. It is a widely used method, especially for plant cells.
Heat shock method: This is a chemical method, primarily used for bacterial transformation. Cells are first made "competent" by treating them with calcium chloride (\(CaCl_2\)), and then they are subjected to a brief, rapid increase in temperature (a heat shock), which temporarily makes the cell membrane permeable to DNA plasmids. It is a standard laboratory method.
Step 3: Final Answer:
Denaturation is a process that affects DNA structure; it is not a tool or method for introducing DNA into a host cell.