Semi-conservative DNA replication is demonstrated by centrifuging DNA from bacteria grown first in heavy nitrogen and then transferred to light nitrogen; the resulting intermediate density indicates each molecule contains one original heavy strand and one newly synthesized light strand.
Semi-conservative DNA replication is shown by growing bacteria in heavy and light nitrogen. DNA from bacteria grown in heavy nitrogen, then placed in light nitrogen, shows intermediate density after centrifugation, indicating each new DNA molecule has one heavy and one light strand.
| Front | Describe experiment showing DNA undergoes semi-conservative replication |
|---|---|
| Back | Bacteria grown in heavy and light nitrogen broths, Nitrogen taken up and become part of DNA. Sample of DNA taken from each batch and centrifuged. Heavy DNA settled lower than light. Bacteria grown in Heavy Nitrogen put in light nitrogen broth and then DNA was centrifuged. If DNA conservation orignal Heavy DNA would be intact and new light DNA would settle at top If DNA semi-conservation DNA molecules would contain 1 strand of Heavy Nitrogen and 1 strand of Light Nitrogen. |
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