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In the Meselson-Stahl experiment, 15N-labeled cells were shifted to 14N medium a

ID: 166521 • Letter: I

Question

In the Meselson-Stahl experiment, 15N-labeled cells were shifted to 14N medium at what is designated as generation 0. For the conservative model of replication, what proportion of 15N-15N, 15N- 14N, and 14N-14N would you expect to find after one replication cycle?

15N-15N

15N-14N

14N-14N

25%

12.5%

75%

100%

50%

87.5%

0%

      -       A.       B.       C.       D.       E.       F.       G.   

15N-15N

      -       A.       B.       C.       D.       E.       F.       G.   

15N-14N

      -       A.       B.       C.       D.       E.       F.       G.   

14N-14N

A.

25%

B.

12.5%

C.

75%

D.

100%

E.

50%

F.

87.5%

G.

0%

Explanation / Answer

In meselson and stahl experiment when 15N DNA was shifted to 14N medium amd allowed to replicate. After 1 replication cycle it produced 2 DNA strands per DNA strand introduced in the medium. All of the DNA relicated semiconservatively to produce 100 % 15N - 14N DNA .

so 0% 15N 15N and 0% 14N 14N.