69.7k views
4 votes
What is the X shape in the middle of the B form of DNA is the diffraction signature of what?

User Abdollah
by
8.0k points

1 Answer

4 votes

Answer: The X-shaped pattern observed in X-ray diffraction images of B-DNA corresponds to the helical structure of DNA. This characteristic X-shaped pattern, often called the "X-ray fiber diffraction pattern of B-DNA," was first described by Rosalind Franklin and Raymond Gosling in 1952.

Explanation: Horizontal Lines: The horizontal lines in the X-pattern represent the regular spacing between the bases along the length of the DNA molecule.

Vertical Lines: The vertical lines represent the helical repeat distance, which is the distance between one helical turn of the DNA and the next.

This X-shaped diffraction pattern provided crucial evidence for the helical structure of DNA. James Watson and Francis Crick, who were working on building a model of DNA, used Franklin's X-ray data (which she produced through her X-ray crystallography experiments) along with other experimental data to propose the famous double-helix structure of DNA in 1953. Franklin's data were critical in elucidating the structure of DNA, although her contributions were often overlooked initially.

User Flyingmeatball
by
9.3k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.