Question

The uptake of the recombinant DNA into bacterial cells during molecular cloning is called

transcription

replication

transformation

ligation

selection

Answer 1

The answer is transformation.  

• The uptake of the recombinant DNA into bacterial cells during molecular cloning is called transformation.

DNA cloning is the technique of making multiple copies of a piece of DNA by directing its replication with in host organisms. Transformation is an important step in cloning.

For molecular cloning of a particular piece of DNA or a gene, first we want to insert that piece of DNA into a circular piece of DNA called plasmid. These steps is done by using enzymes like restriction enzymes (for cutting at specific sites of DNA) and DNA ligase (for joining the DNA piece and plasmid DNA). This piece of plasmid DNA ligated with this foreign DNA (The piece of DNA we want to replicate) is called the recombinant DNA.

After ligation, the recombinant DNA is transferred into bacterial cells and these bacteria can take up the recombinant DNA in transformation.

In transformation; the prepared bacterial solution and the DNA are mixed. After that a heat shock is given. By giving heat shock some of the bacteria will take up the DNA. The transformed bacterias are identified by selection techniques like antibiotic selection.

Let's go through the other choices:

• Transcription is the process of copying a DNA to RNA.
• Replication is the process of producing two identical copies of DNA from one original DNA molecule.
• Ligation is the process of joining two DNA pieces.
• Here, selection refers to the selection of transformed(bacteria with the recombinant DNA) and non-transformed bacteria (that not take up the recombinant DNA) by techniques like antibiotic selection.