Biotechnology: Principles and Processes
Read the following passage carefully and answer the given questions.
Biotechnology deals with large scale production and marketing of products and processes using live organisms, cells or enzymes. Modern biotechnology using genetically modified organisms was made possible only when man learnt to alter the chemistry of DNA and construct recombinant DNA. This key process is called recombinant DNA technology or genetic engineering. This process involves the use of restriction endonucleases, DNA ligase, appropriate plasmid or viral vectors to isolate and ferry the foreign DNA into host organisms, expression of the foreign gene, purification of the gene product, i.e., the functional protein and finally making a suitable formulation for marketing. Restriction endonucleases are used in genetic engineering to form ‘recombinant’ molecules of DNA, which are composed of DNA from different sources (genomes). Vectors used at present, are engineered in such a way that they help easy linking of foreign DNA and selection of recombinants from non-recombinants.
At present more than ______ restriction enzymes have been isolated from several strains of bacteria.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 900
Restriction endonucleases are enzymes that cut DNA at a particular base sequence, called the recognition sequence. The first one isolated, Hind II, always cut DNA at a specific sequence of six base pairs. Today more than 900 restriction enzymes are known. They have been isolated from over 230 strains of bacteria, and each recognises a different sequence.
Note: This passage is taken from NCERT as it is. Most CUET (UG) questions come straight from NCERT, so study the book line by line, including figures and their titles.
NCERT Extract:
Restriction Enzymes –
