Mix radioactively labeled phages with bacteria. The phages infect the bacterial cells. Agitate in a blender to separate phages outside the bacteria from the cells and their contents. Centrifuge the mixture so bacteria form a pellet at the bottom of the test tube. Measure the radioactivity in the pellet and the liquid.
The two strands of the parental molecule separate, and each functions as a template for synthesis of a new complementary strand.
Each strand of both daughter molecules contains a mix of old and newly synthesized parts.
Tested the three models ofDNA replication by this: bacteria cutured in medium containing 15N and then is transferred to medium containing 14N. The different isotope of nitrogen was distinguishable so after DNA samples were centrifuged, one could tell which model was correct.
This is where the sugar-phosphate backbone terminates with the phosphate group attached to the 5' carbon of the last nucleotide.
where DNA polymerases add nucleotides
DNA polymerases add nucleotides only to the free 3' end of a growing DNA strand.
This strand is made starting from the direction away from the replication fork. This is synthesized in a series of short segments.
This ligates (joins) the sugar-phosphate backbones of the Okazaki fragments to create a single DNA strand.
This is an enzyme that joins RNA nucleotides to make the primer. This can start an RNA chain from scratch.
This is an enzyme that untwists the double helix at the replication fork, separating the two old strands.
single-strand binding protein
These line up along the unpaired DNA strands, holding them apart while they serve as templates for the synthesis of new complementary strands.