Final answer:
A restriction enzyme creates sticky ends, which can bond with complementary DNA fragments cut by the same enzyme, and DNA Ligase seals these fragments to form recombinant DNA.
Step-by-step explanation:
A restriction enzyme that makes single-stranded ends that will hydrogen bond to other DNA fragments cut with the same restriction enzyme produces sticky ends. These sticky ends are able to come back together by hydrogen bonding with complementary overhangs on a piece of DNA cut with the same restriction enzyme.
During ligation, these sticky ends are joined by the enzyme DNA Ligase, thus creating a continuous double-stranded DNA molecule, which is a critical step in the formation of recombinant DNA. An enzyme called ligase glues the annealed fragments together. Sticky ends are single-stranded overhangs created by the restriction enzyme that can base-pair with complementary overhangs on other DNA fragments.