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

ID: 166474 • 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 three replication cycles?

15N-15N

15N-14N

14N-14N

25%

50%

0%

87.5%

100%

75%

12.5%

      -       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.

50%

C.

0%

D.

87.5%

E.

100%

F.

75%

G.

12.5%

Explanation / Answer

In meselson stahl experiment when 15N 15N DNA was shifted to 14N medium and after 3 cycles of replication, each strand DNA produced 8 strands of DNA semiconservatively. Out of which, 25 % were 15N - 14N and 75% were 14N - 14N.

No DNA with 15N - 15N was found