When I read about recombinant DNA, I felt both excited and cautious. The process starts with cutting donor DNA and a plasmid vector using the same restriction enzymes, creating complementary sticky ends. I practiced naming enzymes like EcoRI and HindIII, then sketched how they recognize palindromic sequences and cleave phosphodiester bonds.
Next came ligation with DNA ligase, sealing the joint between vector and insert. I drew the circular plasmid map showing antibiotic-resistance gene, origin of replication, and the inserted foreign gene. Transforming E. coli with heat-shock or electroporation and then plating on selective media brought everything to life in the lab.
Sample SPM Question
“Describe how restriction enzymes and DNA ligase are used in creating recombinant DNA.”
• Restriction enzymes cut both plasmid and donor DNA at specific sites to generate matching sticky ends.
• DNA ligase joins the sugar-phosphate backbones, sealing the recombinant molecule.
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