Which of the following enzyme is used to covalently bond foreign DNA to a vector plasmid

The enzyme used to covalently bond foreign DNA to a vector plasmid is called DNA ligase. DNA ligase catalyzes the formation of a phosphodiester bond between the 3' hydroxyl end of one DNA strand and the 5' phosphate end of another DNA strand. This enzyme is crucial in the process of DNA cloning, where foreign DNA (such as a gene of interest) is inserted into a vector plasmid.

Here is how DNA ligase is typically used in the process of inserting foreign DNA into a vector plasmid:

1. Preparation of DNA: Both the foreign DNA and the vector plasmid are typically cut using the same restriction enzyme(s) to create compatible cohesive (sticky) or blunt ends.

2. Mixing DNA: The foreign DNA and vector plasmid are mixed together, allowing the compatible ends to anneal (pair).

3. Ligation: DNA ligase is added to the mixture. The enzyme forms covalent bonds between the adjacent nucleotides on the foreign DNA and vector plasmid, effectively sealing the foreign DNA into the vector.

4. Transformation: The newly formed recombinant plasmid can then be introduced into a host cell for replication and expression of the foreign DNA.

DNA ligase is a key enzyme in molecular biology techniques such as cloning, where it is used to join DNA fragments together to create recombinant DNA molecules.