Question
E. coli about to replicate was placed in a medium containing radioactive thymidine for five minutes. Then, it was made to replicate in a normal medium. Which of the following observation shall be correct?
Both strands of DNA will be radioactive
One strand is radioactive
Each strand is half radioactive
None is radioactive
DNA replication follows a semiconservative mechanism . When E. coli incorporates radioactive thymidine during its initial replication, the newly synthesised strands become radioactive. If these bacteria are then transferred to a normal medium for further replication, the radioactive strands act as templates for the synthesis of new, non-radioactive complementary strands . Following the Watson-Crick model, each resulting daughter DNA molecule will possess one parental strand and one newly synthesised strand . Consequently, in the hybrid molecules formed, one strand is radioactive while the other is normal. This principle was experimentally proven by Taylor and colleagues using radioactive thymidine . Mastering these molecular biology experiments is a critical strategy, as NCERT textbooks serve as the primary source for approximately 95% of NEET Biology questions .
This question aligns with the NEET BIOLOGY syllabus, specifically targeting concepts from Molecular Basis of Inheritance. Mastering this topic is crucial for scoring well in the upcoming medical entrance examinations. Solving conceptually related problems will help you understand the nuances of these concepts and improve your problem-solving speed.
More Molecular Basis of Inheritance Questions
Which scientist conducted an experiment with 32P and 35S labelled phages for demonstrating that DNA is the genetic material?
The method of DNA replication in which two strands of DNA separate and synthesize new strands is called:
Which one of the following experiments of Frederick Griffith resulted in the discovery of bacterial transformation?
Given below are two statements: Statement I: In the RNA world, RNA is considered the first genetic material evolved to carry out essential life processes. RNA acts as a genetic material and also as a catalyst for some important biochemical reactions in living systems. Being reactive, RNA is unstable. Statement II: DNA evolved from RNA and is a more stable genetic material. Its double helical strands being complementary, resist changes by evolving repairing mechanism. In light of the above statements, choose the most appropriate answer from the options given below:
What is the role of RNA polymerase III in the process of transcription in Eukaryotes?
Which experimental material was used by Taylor and colleagues to prove that DNA in chromosomes replicates semiconservatively?
Which of the following is not a cloning vector?
The association of histone H1 with a nucleosome indicates:
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