A biologist wishes to take a useful gene found in pine trees and introduce it into some bacterial cells. Her experimental procedure is given below.

1. Use a restriction enzyme to cut a gene out of the pine tree DNA.

2. Use a restriction enzyme to cut open a plasmid.

3. Treat the plasmid with DNA ligase.

4. Mix the desired gene and plasmid together.

5. Introduce the plasmid into bacterial cells.

Which steps should be switched in the biologist's procedure?

A. 3 and 4

B. 1 and 3

C. 2 and 3

D. 4 and 5

option A

Explanation:

In Recombinant DNA technology which involves DNA molecules formed by recombination to bring together genetic material from different sources, producing sequences that would normally not be found in the genome. Some basic steps are to be followed in the formation of your recombinant DNA. The restriction enzyme used in cutting the gene of interest from the pine tree DNA should also be the same used in cutting open the plasmid to make complementary sticky ends. Then integration of the isolated gene of interest into the cut plasmid and then this is treated with ligase to join the cut sticky ends. This construct is then introduced into bacterial cells.