Question

Please list and explain the different types of plasmids in regards to microbiology and whether or not having one plasmid influences getting another plasmid.

Answer 1

Plasmid in bacteria are classified into two types-

1) Conjugative plasmid 2) Non-conjugative plasmid.

Conjugative plasmid contains transfer gene(tra gene) which promotes sexual conjugation between two cells whereas Non-conjugative plasmid doesn't contain any such genes and needs the help of conjugative plasmid for sexual conjugation.

Plasmids are also classified into 5 classes on the basis of function. The 5 classes are-

1) Fertility/F-plasmid- These plasmids contain tra genes and are capable of sexual conjugation.

2) Virulence plasmids- These plasmids contain virulence genes and are capable of turning a bacteria into pathogen.

3) Resistance/R-plasmid- These plasmids contain genes that provide protection/resistance from antibiotics.

4) Col plasmid- These plasmids contain genes that code for proteins like bacteriocins that kills other bacteria.

5) Degradative plasmids- These plasmids take part in breakdown of substances like toluene,etc.