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During Meselson and Stahl’s experiments, heavy DNA was distinguished from normal DNA by centrifugation in

a)

CsOH gradient

b)

c)

d)

CsCl gradient



Question ID - 1195 | SaraNextGen Top Answer

During Meselson and Stahl’s experiments, heavy DNA was distinguished from normal DNA by centrifugation in

a)

CsOH gradient

b)

c)

d)

CsCl gradient

1 Answer
127 votes
Answer Key / Explanation : (d) -

(d)

In Meselson and Stahl’s experiment, bacterial cells were grown for several generations in a medium containing a heavy isotope of nitrogen  and then, were transferred to a new medium containing the normal lighter isotope . At various times thereafter, samples of bacteria were collected and their DNA was dissolved in a solution of cesium chloride, which was spun rapidly in a centrifuge. Because the cesium ion is so massive, it tends to settle towards the bottom of the spinning tube, establishing a gradient of caesium density.

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