Question

_{1)   What is a plasmid and describe 2 common uses of plasmids in biological research (3)Need circular piece of DNA.
2) What 3 key/critical features do almost all plasmids share.}

Answer 1

1) Plasmids are autonomous self replicating DNA molecules that are maintained as discrete, extrachromosomal genetic materials in bacterial cells. Most plasmids are circular, supercoiled dsDNA molecules but there are also some linear plasmids.

The two common uses of plasmids in biological research are :

• Plasmid DNA are used for genetic engineering purposes where transfer of external DNA or any useful genes can be done by using the plasmid as a vector
• Plasmids are used for production of antibiotics . Plasmids contain antibiotic resistance genes and thus can be used to induce the antibiotic formation by expressing the antibiotic genes

2) The three critical features that all plasmids share are:

• They follow the rolling circle model of replication becuase of their circular structure
• They have a high copy number mostly as they are extensively used in genetic engineering
• They have wide range of genetic material that can be replaced by the gene of interest including the antibiotic resistant genes.