Question

Extranuclear DNA in E. Coli is termed as
A. F- factor
B. Sexfactor
C. Episome
D. All of the above

Answer 1

Hint: Bacterial cells such as E dot coli poses are a single main chromosome in the nucleoid and often extra DNA elements called plasmids in the cytoplasm.

Complete Answer:
- All of the genetic information in a cell was initially thought to be confined to the DNA in the chromosomes of the cell nucleus but now it is known that small circular chromosomes, called extranuclear or cytoplasmic DNA are located in two types of organelles found in the cytoplasm of the cell. These organelles are the mitochondria in animal and plant cells and the chloroplasts in the plant cells.
- F factor is an extra Nuclear DNA found in E coli. It is also known as the fertility factor. A common form of F factor is an F plasmid. It is used to transfer genes from one bacterium to another bacterium by conjugation.
- F factor n E coli is called a sex factor. Episome is also known as a plasmid. It is an extranuclear DNA found in many bacteria, these are the eukaryotic equivalent of bacterial plasmids. It gives a selective advantage to bacteria carrying it. For example, it contains antibiotic resistance genes.

So, the correct answer is option D.

Note: The cells of several groups of organisms contain small extra DNA molecules called plasmids. Bacterial plasmids are circular DNA molecules, some carry genes for resistance to various agents in the environment that would be toxic to the bacteria for example antibiotics. The fertility factor allows genes to be transferred from one bacterium carrying the factor to the other bacterium lacking the factor by the process of conjugation. The effect is carried on the F episode comma, the first episode to be discovered.