AP BIOLOGY

Detailed explanation-1: -Restriction enzymes are DNA-cutting enzymes. Each enzyme recognizes one or a few target sequences and cuts DNA at or near those sequences. Many restriction enzymes make staggered cuts, producing ends with single-stranded DNA overhangs.

Detailed explanation-2: -Both the plasmid (blue, backbone) and the DNA sequence of interest (green, insert) are cut with restriction enzymes to generate compatible overhangs that allow them to bind. Ligase is used to make bonds between the insert and backbone covalent.

Detailed explanation-3: -SmaI is an example of a restriction enzyme that cuts straight through the DNA strands, creating DNA fragments with a flat or blunt end. Other restriction enzymes, like EcoRI, cut through the DNA strands at nucleotides that are not exactly opposite each other.

Detailed explanation-4: -The restriction enzymes cuts at fixed sequences, therefore same restriction enzyme must be used since it forms fragments with complementary sticky ends, therefore facilitating the formation of bonds between them.