AP BIOLOGY

Detailed explanation-1: -Although Cas9 is the enzyme that is used most often, other enzymes (for example Cpf1) can also be used. Once the DNA is cut, researchers use the cell’s own DNA repair machinery to add or delete pieces of genetic material, or to make changes to the DNA by replacing an existing segment with a customized DNA sequence.

Detailed explanation-2: -Restriction enzymes are also called “molecular scissors” as they cleave DNA at or near specific recognition sequences known as restriction sites. These enzymes make one incision on each of the two strands of DNA and are also called restriction endonucleases.

Detailed explanation-3: -Restriction enzymes are specific as they cut the internal phosphodiester bond of DNA molecule at a specific nucleotide sequence. This sequence is called as restriction site. It is widely used in genetic engineering and also called molecular scissor.

Detailed explanation-4: -Genetic engineering is accomplished in three basic steps. These are (1) The isolation of DNA fragments from a donor organism; (2) The insertion of an isolated donor DNA fragment into a vector genome and (3) The growth of a recombinant vector in an appropriate host.