Biotechnology Principles and Processes MCQs for NEET — Zoology Questions with Answers

The NCERT mentions, 'In another method, suitable for plants, cells are bombarded with high velocity micro-particles of gold or tungsten coated with DNA in a method known as biolistics or gene gun.'

The text states, 'In a chromosome there is a specific DNA sequence called the origin of replication, which is responsible for initiating replication. Therefore, for the multiplication of any alien piece of DNA in an organism, it needs to be integrated...'

The NCERT states, 'Similarly, retroviruses in animals have the ability to transform normal cells into cancerous cells. A better understanding of the art of delivering genes by pathogens in their eukaryotic hosts has generated knowledge to transform these tools of pathogens into useful vectors for delivering genes of interest to humans.'

While competence can refer to various cells, the most direct and common method described for making host cells (specifically referring to 'Recipient cells after making them ‘competent’ to receive, take up DNA present in its surrounding') is in the context of bacterial transformation using heat shock/chilling protocol for plasmid uptake. The subsequent example given is 'if a recombinant DNA bearing gene for resistance to an antibiotic (e.g., ampicillin) is transferred into E. coli cells...'

The NCERT explains, 'If we spread the transformed cells on agar plates containing ampicillin, only transformants will grow, untransformed recipient cells will die.' This principle is used for selection, where the ampicillin resistance gene acts as a selectable marker.

The NCERT states, 'we have learnt the lesson of transferring genes into plants and animals from bacteria and viruses which have known this for ages – how to deliver genes to transform eukaryotic cells... For example, Agrobacterium tumifaciens... is able to deliver a piece of DNA known as ‘T-DNA’ to transform normal plant cells...'

The NCERT specifies, 'In another method, suitable for plants, cells are bombarded with high velocity micro-particles of gold or tungsten coated with DNA in a method known as biolistics or gene gun.'

The NCERT text states: 'Origin of replication (ori) : This is a sequence from where replication starts and any piece of DNA when linked to this sequence can be made to replicate within the host cells. This sequence is also responsible for controlling the copy number of the linked DNA.'

The NCERT text mentions: 'The ligation of alien DNA is carried out at a restriction site present in one of the two antibiotic resistance genes. For example, you can ligate a foreign DNA at the BamH I site of tetracycline resistance gene in the vector pBR322. The recombinant plasmids will lose tetracycline resistance due to insertion of foreign DNA but can still be selected out from non-recombinant ones by plating the transformants on ampicillin containing medium.'

The NCERT text states: 'In order to link the alien DNA, the vector needs to have very few, preferably single, recognition sites for the commonly used restriction enzymes. Presence of more than one recognition sites within the vector will generate several fragments, which will complicate the gene cloning.'