Question

The DNA of E.coli is
A. Double-stranded circular
B. single-stranded circular
C. Double-stranded linear
D. Single-stranded linear

Answer 1

Hint: E. coli is the intestinal bacteria that are normally available in the human intestine but also present in the intestine of other animals. As it is microscopic and its size is also small, bacteria are prokaryotic and it is about one-tenth of the size of eukaryotic cells and typically range in 0.5-5.0 micrometre in length.

Complete answer: E. coli or Escherichia coli is gram-negative and a facultative bacteria that appears to be rod-shaped. The coliform bacteria belong to the genus Escherichia that is normally found in the intestine of the eurythermal (warm-blooded) organisms and does not cause any illness, but some of the strains of E. coli may cause food poisoning. Its genetic material is DNA. Few of them are used in the recombinant DNA technology and other industries to obtain the desired product. E. coli is one of the most varied bacterial species. Only twenty percent of genes are common in all E. coli strains. The DNA sequencing of the E. coli gene was carried out in 1997. It was the first complete DNA sequencing. It holds circular DNA that has 4.6 million base pairs.
Hence, the correct answer is option A.

Note: Basically, prokaryotic cells like bacteria and viruses are the smallest living creature that is microscopic in nature. They possess either DNA and RNA as single-stranded or double-stranded. Viruses are microscopic entities that are smaller than bacteria and act as a non-living organism when it is found outside the host cell.