Question

Can somebody answer these two questions? I need it fast!

1. Watson and Crick knew that the triple helix model of DNA that Linus Pauling had proposed was incorrect. What evidence did they have for such a conclusion?


2. The work of Rosalind Franklin provided a key piece of data for Watson and Crick’s model of DNA.  Summarize that evidence and how it was pivotal to the correct model being built.

Answer 1

2. Working with a student, Raymond Gosling, Franklin was able to get two sets of high-resolution photos of crystallized DNA fibers. She used two different fibers of DNA, one more highly hydrated than the other. From this she deduced the basic dimensions of DNA strands, and that the phosphates were on the outside of what was probably a helical structure.
She presented her data at a lecture in King's College at which James Watson was in attendance. In his book The Double Helix, Watson admitted to not paying attention at Franklin's talk and not being able to fully describe the lecture and the results to Francis Crick. Watson and Crick were at the Cavendish Laboratory and had been working on solving the DNA structure. Franklin did not know Watson and Crick as well as Wilkins did and never truly collaborated with them. It was Wilkins who showed Watson and Crick the X-ray data Franklin obtained. The data confirmed the 3-D structure that Watson and Crick had theorized for DNA. In 1953, both Wilkins and Franklin published papers on their X-ray data in the same Nature issue with Watson and Crick's paper on the structure of DNA.

Source: http://www.dnaftb.org/19/bio-3.html

Answer 2

She used two different fibers of DNA, one more highly hydrated than the other. From this she deduced the basic dimensions of DNA strands

The data confirmed the 3-D structure that Watson and Crick had theorized for DNA

Answer 3

I hope this helps!