Discovering the double helix structure, James Watson
Interviewee: James Watson. James Watson talks about how he worked out the base pairing of DNA. (DNAi Location: Code > Finding the structure > players > James Watson and Francis Crick > Base pairing)
Well, it's too much effort to draw them out on paper each time and get the bond angles and bond lengths right, best to, you know, make out some cardboard cut outs. So I just used ordinary sort of thin pieces of white covered smooth cardboard, and attached to them hydrogen atoms, I made these six to nine member rings and then distinguished adenine and guanine or thymine and... by little sticks which said here is a hydrogen atom at the tip and if you have a good hydrogen bond it should immediately, it should point directly at the acceptor. And so I finally put those together, didn't really have them in good shape until early Saturday morning February 28th. I got in early and finally was going to see which one fits together. And Francis had kept telling me, well you know, there's Chargaff's pairs, would they pair to each other. And, but I didn't like Chargaff, ever since I had met him a year before, I thought I don't want to use his data in finding the structure, boy it was really stupid. And, but I couldn't help, you know, just switching around on the table to see that adenine and thymine had a, formed a very nice base pair and guanine and cytosine formed one identical in shape, and I thought you can build a double helix with adenine and thymine and guanine and cytosine base pairs.
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15492. Discovering the double helix structure of DNA, James Watson, video with 3D animation and narration
James Watson used cardboard cutouts representing the shapes of the DNA bases to figure out how bases pair.
James Watson and Francis Crick explain how they solved the structure of DNA. Erwin Chargaff explain how he measured the levels of each of the four nitrogenous bases.
DNA base pairs
1953 picture of Francis Crick (L) and James Watson (R) walking along the backs of King's College in Cambridge.
In 1953, James Watson and Francis Crick solved the structure of DNA. This beautiful molecule sparked a new era of research into the code of life.
Explore DNA's structure.
Deoxyribose and phosphate molecules form the uprights and nucleotide pair form the rungs of the DNA ladder.
Because it contains the directions for assembling the components of the cell, DNA is often thought of as the "instruction book" for assembling life.
Animation of 2D DNA model becoming three dimensional.
James Watson describes the triple helix model proposed by Linus Pauling.