Small circular molecules of "extra" DNA in bacteria are called?

a. plasmids.





b. desmids.





c. pili.





d. F particles.





e. transferins

Small circular molecules of "extra" DNA in bacteria are called?
a. plasmids.
Reply:a - this is where the gene for insulin is added when producing genetically modified bacteria to make human insulin (for diabetics)
Reply:Plasmids - circular pieces of extra-chromosomal DNA
Reply:The answer is:


a) Plasmids.





Some more information about Plasmid :





A plasmid is a DNA molecule separate from the chromosomal DNA and capable of autonomous replication. It is typically circular and double-stranded. It usually occurs in bacteria, sometimes in eukaryotic organisms. Size of plasmids varies from 1 to over 400 kilobase pairs (kbp). There may be one copy, for large plasmids, to hundreds of copies of the same plasmid in a single cell, or even thousands of copies, for certain artificial plasmids selected for high copy number . Plasmids can be part of the mobilome, since they are often associated with conjugation, a mechanism of horizontal gene transfer.





The term plasmid was first introduced by the American molecular biologist Joshua Lederberg in 1952.