Question

Ten E.coli cells with ${}^{15}N-dsDNA$ are incubated in medium containing ${}^{14}N$ nucleotide. After $60$ minutes, how many E.coli cells will have DNA totally free from ${}^{15}N$ ?

• A. 80 cells
• B. 20 cells
• C. 40 cells
• D. 60 cells

Answer 1

Answer: (D)

Correct answer is (d) 60 cells