Watson-Crick DNA Double Helix Model — NEET Biology
✅ Asked in NEET 2024DNA as an acidic substance present in nucleus was first identified by Friedrich Meischer in 1869. He named it as 'Nuclein'. However, due to technical limitation in isolating such a long polymer intact, the elucidation of structure of DNA remained elusive for a very long period of time. It was only in 1953 that James Watson and Francis Crick, based on the X-ray diffraction data produced by Maurice Wilkins and Rosalind Franklin, proposed a very simple but famous Double Helix model for the structure of DNA. One of the hallmarks of their proposition was base pairing between the two strands of polynucleotide chains. However, this proposition was also based on the observation of Erwin Chargaff that for a double stranded DNA, the ratios between Adenine and Thymine and Guanine and Cytosine are constant and equals one.
NTA tests your understanding of the Watson-Crick Double Helix model and the evidence supporting it, particularly X-ray diffraction data and Chargaff's rules. Students often confuse who discovered what: Meischer identified DNA as 'Nuclein' in 1869, but Watson-Crick proposed the structure in 1953 using data from Wilkins and Franklin. A common trap is forgetting Chargaff's base-pairing ratios (A=T and G=C) which were crucial to the model's foundation. Remember: the Double Helix is antiparallel with complementary base pairing, and this entire structure was deduced from X-ray diffraction patterns, not direct observation.
Which of the following techniques was used to elucidate the double helix model of DNA?
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