In 1953 James Watson and Francis Crick tomorrow
of the structure of DNA printable features of which are still accepted today they have
a consistent two strands that are complimentary and the sequences to each other as cytosine
base once try and always pairs with a guanine base on the other hand adenine base and once
try and always pairs with a thymine base on the other the complementary nature of the
two strands suggested to the scientists are for DNA replication proposed that the old
strand service templates to make new complementary strands that are resulting WSE’s with each
containing one and one old’s grand there are other models to consider as well resemble
the old DNA molecule could be preserved and an entire wing DNA molecule can be produced
from it you result of the application will be to molecules with old and new DNA interspersed
needs to add from your knowledge of DNA replication which one of these models is correct click
on the correct model from your knowledge of DNA replication drag the correct names to
the three models of DNA replication Watson and Crick proposed a model of semiconservative
replication at the time no evidence existed to prove that this model was correct to solve
this problem the scientists met in Brussels and infrequent stall designed an experiment
to test Watson and Crick’s model of replication the key to the masses install experiment was
devising a strategy to distinguish between all versus newly synthesised DNA distinguish
the two by labelling them with isotopes they grew Escherichia coli bacteria in the presence
of either a heavy isotope of hydrogen in 15 over the ordinary light isotope 1014 generations
the DNA of the bacteria containing either the heavy or old alike form of nitrogen but
not both in this example the nitrogen atoms in a thymine base are labelled with either
a heavy older white forms of nitrogen the scientists took samples of each bacterial
culture they process the bacteria to release the DNA into solution equal volumes of the
DNA solutions were mixed together and the solution was concentrated solution of the
salt cesium chloride the density of the cesium chloride was 1.71 g/cm� the same density
as DNA that was placed after a centrifuge capable of high-speed centrifugation 140,000
times the force of gravity for 20 hours at this high-speed cesium ions have a tendency
to settlement for the bottom of the tube forming a higher density solution at the bottom compared
to the top other substances such as the DNA to the position within the tube that matches
their own density watchband of DNA contains the heavy isotope in 15 of nitrogen click
on the correct by and with the technique of separating heavy versus White DNA established
the scientists tested the hypothesis of semiconservative replication the first group, why for 14 generations
in a medium within 15 uniform of ammonium chloride as the sole nitrogen source growing
bacteria for many generations ensured that all the DNA would be labelled with heavy nitrogen
at this time the isolated the first bacterial sample prepared the DNA as the cesium chloride
or centrifugation at the same time some of the bacteria were transferred to and 14 light
medium and allowed to continue to grow from this point onward replicated DNA will be made
with the likes form of nitrogen may call their first self generations are well after the
transfer to light medium samples taken every 20 minutes which is the generation time for
E. coli cells growing at the optimal temperature the DNA from the samples was prepared for
high-speed centrifugation vessel is in install for the following results in generation zero
all of the DNA was in the heavy for after one generation the DNA was neither healthy
nor light by an intermediate density after two generations have of the DNA was white
and half was in immediate and traditional generations of the DNA was alike form unless
any intermediate form generation zero through to provide enough information to determine
which model of DNA replication is correct click on the correct model with these hypothetical
data suggest about DNA replication click on the appropriate model to add the appropriate
density profiles to the generations on the left, we have examined whether they would
look like for all three types of replication kid, I’d must also install is wielded a match
with semiconservative replication