Question

In genetic engineering, a DNA segment (gene) of interest, is transferred to the host
cell through a vector. Consider the following four agents (A-D) in this regard and select the correct option about which one or more of these can be used as a vector/vectors.
A) A bacterium
B) Plasmid
C) Plasmodium
D) Bacteriophage

i) (B) and (D) only
ii) (A), (B) and (D) only
iii) (A) only
iv) (A) and (C) only

Answer 1

Hint:The term biotechnology refers to the use of living organisms or their products to modify human health and the human environment. Genetic Engineering: Techniques to alter the chemistry of genetic material (DNA and RNA), to introduce these into host organisms and thus change the phenotype of the host organism.

Complete answer:
Traditional hybridisation procedures used in plant and animal breeding, very often lead to inclusion and multiplication of undesirable genes along with desired genes. The techniques that are involved in genetic engineering include some steps such as creation of recombinant DNA, use of gene cloning and gene transfer overcome this limitation and allow us to isolate and introduce only one or a set of desirable genes without introducing undesirable genes into the target organism.

Vector is a carrier/vehicle that delivers a foreign piece of DNA into the host organism and they are engineered in such a way that they help in following Easy linking of foreign DNA. Selection of recombinants from non-recombinants.

Now let us gather information about given options: -
A bacterium : Bacteria can be used as disease resistant formula and not for the vector as it can cause disease in organisms.
Plasmids :- These are extra chromosomal, circular, non-essential, double-stranded, autonomous, self-replicating pieces of DNA in bacterial and some yeast cells. They may confer the property of antibiotic resistance (bacteria) and virulence (Ti plasmid in Agrobacterium tumefaciens). These plasmid DNA act as vectors to transfer the piece of DNA attached to it into the host organism.
Plasmodium :- The disease causing viruses do not serve as vectors rather they get inside the cell and damages the cell . They cannot be used as vectors as if plasmodium will be used as vector as they will cause malaria
Bacteriophage : It serves as vector due to the occurrence ${\displaystyle \frac{1}{3}}$rd non-essential genome that can be replaced with foreign DNA and essence of the genome to be 40,000 and 53,000 bp long for its packaging makes bacteriophages ideal vector.

Hence the correct answer is option ‘A’ i.e, (B) and (D) means plasmid and bacteriophage.

Note:The production of the first recombinant DNA arrived from the possibility of linking a gene-encoding antibiotic resistance with a native plasmid (autonomously replicating circular extrachromosomal DNA) of Salmonella typhimurium. Stanley Cohen and Herbert Boyer made this possible in 1972 by isolating the antibiotic resistance gene by cutting Out a piece of DNA from a plasmid which was responsible for conferring antibiotic resistance.