Question

Name the enzymes ( which cut the DNA at specific site and ( which join two DNA fragments.

Hint:

Restriction enzymes are crucial in recombinant DNA technology, while DNA ligase is essential for repairing DNA and joining fragments in cloning processes.

Answer 1

Step 1: Enzymes that cut DNA.
((A) The enzymes that cut DNA at specific sites are called Restriction enzymes or Restriction endonucleases. They recognize specific sequences in the DNA and cut between particular nucleotide bases. Examples include EcoRI, HindIII, etc.
Step 2: Enzymes that join DNA fragments.
((B) The enzyme that joins two DNA fragments is called DNA Ligase. It forms phosphodiester bonds between the sugar-phosphate backbones of the DNA fragments, thereby joining them.
Final Answer: \[ \boxed{\text{((A) Restriction enzymes, ((B) DNA ligase}} \]