Question

The DNA of E.coli is

• A. double stranded and linear
• B. double stranded and circular
• C. single stranded and linear
• D. single stranded and circular.

Hint:

The intestinal bacteria, E. coli, are available in the human intestine but also in the intestine of other animals.

Answer 1

The Correct Option is B

E. coli is a gram-negative, rod-shaped, motile or nonmotile bacteria. 

• It contains double-stranded DNA. 
• The DNA in E.Coli is not associated with any histone proteins, hence it is known as naked DNA. 
• This DNA has no free ends and is circular.

Therefore, option B) is the correct answer.

Answer 2

The intestinal bacteria, E. coli, are available in the human intestine but also in the intestine of other animals. As the bacteria are microscopic, it ranges from 0.5 to 5.0 micrometres in length.

Complete answer:

E. coli (Escherichia coli) is gram-negative bacteria in the shape of a rod. 

• The coliform bacteria belong to the Escherichia genus. 
• E. coli is the most varied bacterial species. 
• The DNA sequencing of E. coli was carried out in 1997. 
• It has circular DNA with 4.6 million base pairs.

Hence, the correct answer is option B) The DNA of E.coli is double-stranded and circular.