Question

Calculate the number of nitrogen bases in E.coli, if the length of E.coli DNA is 1.36 mm.

• A. $4\times {10}^6$
• B. $8\times {10}^6$
• C. $2\times {10}^6$
• D. $16\times {10}^6$

Answer 1

The correct option is A $4\times {10}^6$

The distance between two base pairs is 0.34 X 10${}^{-9}$ m. The total length of DNA in E. coli is 1.36 mm.

Total length of DNA = the total number of base pairs x distance between two consecutive base pairs

Hence, total number of base pairs = total length of DNA / distance between two consecutive base pairs

= 1.36 / 0.34 X 10${}^{-9}$ = 4 X 10${}^6$ base pairs.

Thus, the correct answer is '4 x 10${}^6$.'