Question

Which of the following restrictions enzymes produce blunt ends?
A. Xho 1
B. Hind 3
C. Sal 1
D. Eco RV

Answer 1

Hint: The recombination is one of the most used techniques in the biotechnology fields. It is used for the production of mixed featured organisms which have characters from different organisms. They can be recombined at the genetic level and introduced into a host to develop. For this to occur, there has to be a cut in the existing plasmid to enter the new gene.

Complete answer:
Cloning vectors is a vehicle used to artificially carry the foreign gene into a host. The gene can be expressed in the host. All the cloning vectors have an ori site, multi cloning site and selectable marker. The various cloning vectors used are- plasmid, cosmids, bacteriophages, YAC, BAC and phages.
It has the origin of replication sites(ori). It has more than 40 restriction sites. This number is unique to every cloning vector. There are 11 sites in the tetracycline resistance site and 6 main restriction sites in the ampicillin restriction gene.
EcoRI, HindIII and BamHI are some of the restriction enzymes on the PBR322.
Restriction enzymes are the proteins that will cut DNA only at a specific site. It is a sequence of nucleotides which is very specific for its site of the cut. There are more than 400 restriction enzymes available.
The restriction site is the target place in the plasmid. They are usually abstracted from the bacteria.
When they mark a cut on the plasmid, they can produce either blunt ends or sticky ends.
Blunt ends are produced when the cut of endonuclease is placed in somewhere centre of the sequence.
Sticky ends are produced when the cut by the restriction enzymes is made at the terminal sites providing loose bonds.
Option A: Xho 1: It is isolated from Xanthomonas campestris. It cuts at the ends thereby giving sticky ends.
Option B: Hind 3: It is a type 2 restriction endonuclease which gives sticky ends. It is isolated from Haemophilus influenzae.
Option C: Sal 1: This restriction enzyme is obtained from Streptococcus albus. It produces sticky ends.
Option D: Eco RV: It is type 2 endonuclease producing blunt ends in the centre of nucleotide sequence GAT/ATC.

So, the answer is option D: Eco RV.

Note:
PBR322 is a cloning vector in which the recombinant DNA is entered. It was developed by Francisco Bolivar and Raymond Rodriguez. The 322 in PBR322 stands for the plasmid number to distinguish it from other plasmids. It is the first artificial cloning vector produced. There is ROP protein in the PRB322 for keeping the copy number of ColE1 low.