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An enzyme that joins DNA fragments into a continuous molecule.

An enzyme that joins pieces of DNA into a continuous molecule.

Pairing alone does not make one continuous DNA molecule; DNA ligase joins the DNA pieces together.

DNA ligase joins the DNA fragments to make a continuous plasmid containing the inserted gene. This is a recombinant plasmid: its DNA now includes the chosen gene as well as plasmid DNA.

An enzyme that joins DNA fragments by forming bonds in their DNA backbones.

DNA ligase seals the DNA backbones, producing one continuous circular DNA molecule. Because this plasmid contains DNA joined from different sources, it is a recombinant plasmid, a type of recombinant DNA.

Keep the roles distinct: restriction enzymes cut DNA; complementary sticky ends help the pieces line up; DNA ligase joins them permanently.

Keep the roles distinct: restriction enzymes cut DNA, matching sticky ends help the pieces pair, and DNA ligase joins them.

State the enzymes' different roles precisely: a restriction endonuclease cuts DNA at recognised sequences; DNA ligase joins the DNA backbones.