Question

Who amongst the following scientist/s had no contribution in the development of the double-helix model for the structure of DNA?

• A. Maurice Wilkins
• B. Rosalind Franklin
• C. Meselson and Stahl
• D. Erwin Chargaff

Hint:

Timeline trick: The Double Helix structure was proposed in 1953. Meselson and Stahl proved semi-conservative replication later, in 1958.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept: The groundbreaking discovery of the DNA double helix model in 1953 by Watson and Crick was built upon the crucial findings of several other contemporary scientists.
Step 2: Key Formula or Approach: Identify the scientific contributions of each listed scientist to separate the structural discoverers from those who studied DNA function later.
Step 3: Detailed Explanation: Maurice Wilkins and Rosalind Franklin produced critical X-ray diffraction images of DNA, which provided direct physical evidence of its helical structure.
Erwin Chargaff formulated "Chargaff's rules," observing that in double-stranded DNA, the ratio of Adenine to Thymine and Guanine to Cytosine is always equal, which hinted strongly at base pairing.
Watson and Crick used all these findings to propose the double helix model.
However, Matthew Meselson and Franklin Stahl conducted their famous experiment later, in 1958.
Their experiment brilliantly proved that DNA replication is semi-conservative, but they did not contribute to the initial structural modeling of the double helix itself.
Step 4: Final Answer: The scientists with no contribution to the structural model are Meselson and Stahl.