CBSE 2025 · Region 7 · Set 3 · Q17 · 2 marks
How is DNA isolated in purified form from a bacterial cell ?Explain how human functional insulin was produced by using recombinant DNA (rDNA) technology.
How is DNA isolated in purified form from a bacterial cell ?
Explain how human functional insulin was produced by using recombinant DNA (rDNA) technology.
Marking-scheme solution
-DNA from bacteria can be released from the cells by digesting the cell envelope
with enzyme lysozyme.
-Protein and RNA are removed by treating with proteases and ribonuclease
respectively.
-Other molecules can be removed by appropriate treatments.
-Purified DNA ultimately can be precipitated out after the addition of chilled
ethanol.
-Two DNA sequences coding for the polypeptide A and B have been prepared
(in vitro).
-These DNA sequences were introduced into the plasmid of E. coli to produce the
polypeptides.
-Polypeptide chains ‘A’ and ‘B’ were produced separately in the bacterium.
-They have been extracted and combined by creating disulphide bonds to form
human insulin.
Biotechnology : Principles and ProcessesProcesses of Recombinant DNA TechnologyUnderstandvery_short_answermedium
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