Question

Place the following steps of DNA cloning in order:

I. replication generates many copies of DNA fragment
II. Restriction enzyme cuts fragment + plasmid to generate sticky ends
III Plasmid introduced into bacteria
IV. place DNA fragment of interest in a vector

Answer 1

DNA cloning involves cutting a DNA fragment and a plasmid with restriction enzymes to create sticky ends, inserting the DNA fragment into the plasmid, introducing the plasmid into bacteria, and then replicating the DNA fragment within the bacterial cells to produce many copies.

Step-by-step explanation:

The steps of DNA cloning should be placed in the following order:

1. Restriction enzyme cuts fragment + plasmid to generate sticky ends - Enzymes known as restriction endonucleases are used to cut both the DNA fragment of interest and the plasmid, resulting in 'sticky ends' which allows them to anneal.
   
   
2. Place DNA fragment of interest in a vector - The DNA of interest is then inserted into a vector, also known as a cloning vector, which is typically a plasmid.
   
   
3. Plasmid introduced into bacteria - The recombinant DNA molecule, which now includes the DNA fragment of interest, is introduced into bacterial cells.
   
   
4. Replication generates many copies of DNA fragment - Bacterial replication mechanisms are used to generate many copies of the DNA fragment, resulting in a colony of bacterial cells that contain the cloned gene.

Throughout this process, various techniques like ligation, where DNA ligase enzyme 'glues' the annealed fragments together, are used to facilitate the cloning process. The use of cloning vectors which often carry a selectable marker, such as antibiotic resistance gene, ensures that only bacterial cells that successfully took up the plasmid are grown.