Question

Which of the following is not required in the preparation of a recombinant DNA molecule?

• A. Restriction endonuclease
• B. DNA ligase
• C. E. coli
• D. DNA fragments

Answer 1

The correct option is C E. coli

Restriction endonuclease:

Restriction endonucleases are the enzymes which cleave the DNA by digesting phosphodiester bonds at the specific sequences within the DNA. Digestion with restriction enzymes produces multiple DNA fragments.

DNA ligase:

DNA ligase is the enzyme that creates the phosphodiester bond between the nucleotides of DNA fragments and helps to seal them together. To create a recombinant DNA molecule, DNA ligase is used to join the DNA fragment carrying the gene of interest and vector DNA.

DNA fragments:

To create a recombinant DNA, genomic DNA is digested with restriction enzymes to produce multiple DNA fragments one of which contains the gene of interest. This is then ligated with the vector molecule.

E. coli:

E. coli is the host which allows the cloning of recombinant DNA and its expression such as production of recombinant proteins. This bacterium is not required during the synthesis of a recombinant DNA molecule.

Final answer

d. E. coli