Question

Following steps are involved in cloning a eukaryotic gene in a bacterial plasmid vector.
I. Introduction of cloning vector into cells.
II. Insertion of eukaryotic DNA into the vector.
III. Identification of cell clones that carry the inserted eukaryotic gene.
IV. Isolation of the vector and the eukaryotic gene-source DNA.
V. Cloning of cells (and foreign DNA).
All of the following statements is true about restriction enzymes except

• A. Each restriction enzyme recognizes a specific sequence of bases on the DNA molecule
• B. Each restriction enzyme cuts at random locations along the DNA molecule
• C. Most restriction enzymes are named after the bacterial organism from which they were first isolated
• D. Restriction enzymes protect their bacterial host against intruding foreign DNA from viruses or other bacterial cells
• E. When a particular sequence of DNA is digested with a specific restriction enzyme, the resulting set of restriction fragments will usually be the same

Answer 1

The correct option is B Each restriction enzyme cuts at random locations along the DNA molecule

DNA fragments to be cloned in DNA vector can be fragmented by using restriction enzymes. Restriction enzymes are specific to bacteria which recognize 4-8 base pair specific sequences present in DNA. The site where restriction enzymes act are called as a restriction site. As these enzymes cleave DNA inside the molecule, these enzymes are also called restriction endonucleases. Thus, the correct answer is option B.