Question

E. coli, in which both the strands of DNA are labeled with ¹⁵N is transferred to ¹⁴N medium and allowed to replicate for three generations. What would be the number of hybrid DNA molecules in the third generation?

Options

• 2

• 4

• 8

• 10

Answer 1

2

Explanation:

Because there will only be two template strands of ¹⁵N DNA in any subsequent generation grown in ¹⁴N media, only two hybrid DNA molecules will be produced.