Question

A biologist isolated a gene from a human cell, attached it to a plasmid and inserted the plasmid into a bacterium. The bacterium made a new protein, but it was nothing like the protein normally produced in a human cell. Why?

• A. The gene contained introns
• B. The gene did not have sticky ends
• C. The biologist should have cloned the gene
• D. The bacterium had undergone a transformation

Answer 1

The correct option is A The gene contained introns

A biologist isolated a gene from a human cell, attached it to a plasmid and inserted the plasmid into a bacterium. The bacterium made a new protein, but it was nothing like the protein normally produced in a human cell, i.e. insulin. It is because of the presence of introns on the gene.

An intron is a long stretch of noncoding DNA found between exons (or coding regions) in a gene. Genes that contain introns are known as discontinuous or split genes as the coding regions are not continuous.