Learn Unit 4- Biotechnology and Its Applications with Free Lessons & Tips

It's not possible for alien DNA to become part of a chromosome anywhere along its length and replicate normally because the cellular machinery and regulatory mechanisms of the host organism are highly specific to its own DNA. Alien DNA would not be recognized properly and integrated into the host genome.

When an alien gene is ligated at the Sal I site of pBR322 plasmid, it means that the gene has been inserted into the plasmid DNA at a specific location determined by the Sal I restriction enzyme recognition site. This process is typically performed using recombinant DNA technology, allowing researchers to create a recombinant plasmid that carries the desired gene. This plasmid can then be used for various purposes in biotechnology.

Uses of cloning vectors in biotechnology include:

1. Gene cloning: Cloning vectors are used to replicate and produce multiple copies of a specific gene of interest.
2. Gene expression studies: Cloning vectors can be used to introduce genes into host organisms for the purpose of studying gene expression and regulation.
3. Protein production: Cloning vectors can be used to express and produce proteins of interest in large quantities for various applications, such as pharmaceuticals or industrial processes.

Biotechnologists refer to Agrobacterium tumefaciens as a natural genetic engineer of plants because this bacterium has the ability to transfer a segment of its DNA (Ti plasmid) into the genome of plant cells, causing them to develop tumors. This natural ability to transfer genetic material makes Agrobacterium tumefaciens a valuable tool in genetic engineering and plant biotechnology.

It is essential to have a selectable marker in a cloning vector to identify and select for cells that have successfully taken up the vector during the cloning process. Selectable markers, such as antibiotic resistance genes, allow researchers to distinguish between cells that have incorporated the vector and those that have not.