Question

The plasmids commonly used in gentic engineering are

• A. extrachromosomal $DNA$
• B. nuclear $DNA$
• C. membrane bound organelles
• D. $DNA$ attached to mitochondria

Answer 1

Answer: (A)

extrachromosomal $DNA$

Answer 2

Plasmid is extrachromosomal $DNA$ present in many bacterial cells. It is a very small piece of circular $DNA$. It is of immense importance in bacterial life as presence of a plasmid may confer resistance to one or more antibiotics upon the bacterial cell. Desired pieces of $DNA$ can be inserted into plasmids, as done in genetic engineering. Eukaryotic genes can be inserted into plasmids and cloned in E.coli. So industrial production of some valuable proteins (e.g; human insulin, growth hormone, antigens for vaccine, etc.) became successful with the help of plasmids.