Question

Direct visual selection method for the selection of recombinant host cells based on their inability to produce color in the presence of chromogenic substrate can be applied if the vector used is a
(a) Modified plasmid vector of E.coli
(b) Modified bacteriophage
(c) Modified Agrobacterium tumefaciens plasmid
(d) Disarmed retrovirus

Answer 1

Hint: Biotechnology is concerned with the large-scale production and marketing of products and processes that involve the use of living organisms, cells, or enzymes. Only when man discovered how to change the chemistry of DNA and construct recombinant DNA was modern biotechnology with genetically modified organisms possible.

Complete answer:
Recombinant DNA (rDNA) molecules are DNA molecules created by laboratory genetic recombination methods (such as molecular cloning) that combine genetic material from multiple sources to create sequences not found in the genome.
A piece of DNA that has been created by combining at least two fragments from two different sources is known as recombinant DNA. Because DNA molecules from all organisms have the same chemical structure, recombinant DNA is possible. The only difference is the nucleotide sequence within that identical overall structure.
Chimeric DNA is a term used to describe recombinant DNA molecules that are made up of material from two different species, similar to the mythical chimera. Palindromic sequences are used in R-DNA technology, which results in sticky and blunt ends.
DNA sequences used to make recombinant DNA molecules can come from any species. Plant DNA, for example, can be linked to bacterial DNA, and human DNA can be linked to fungal DNA. Furthermore, DNA sequences that do not exist in nature can be created and incorporated into recombinant molecules using a chemical synthesis of DNA.
When DNA methyltransferase genes are introduced into E. coli cells, these enzymes modify the transformed plasmids. Plasmid Artificial Modification is a new technique that we propose (PAM). A modified plasmid vector of E.coli is used to introduce recombinant DNA into a host cell and is an important part of molecular cloning, which is the process of creating DNA molecules and introducing them into a host cell.
Direct visual selection method for the selection of recombinant host cells based on their inability to produce color in the presence of chromogenic substrate can be applied if the vector used is a Modified plasmid vector of E.coli is used.

Thus, the answer is option A: Modified plasmid vector of E.coli.

Note: In most cases, recombinant DNA-containing organisms appear to have normal phenotypes. That is, their appearance, behavior, and metabolism are usually unaffected, and the only way to detect recombinant sequences is to look at the DNA itself, which is usually done with a polymerase chain reaction (PCR) test.