Question

Consider a DNA molecule which contain most of its nitrogen in the form of 15N. Such molecules are
allowed to replicate in an environment where the nitrogen source is 14N. What will be the proportion of
DNA molecules that will contain 14N only after three round of replication.
1) 25% 2) 50%
3) 75% 4) 100%

Answer 1

Answer:

75%

Explanation:

In every generation there will be two hybrids, other DNA molecules will contain N14

After three round of replication, there will be 8 new DNA strands. In which 6 will contain N14

6/8 x 100 = 75%

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