This is my report about the discovery of the structure of

deoxyribose nucleic acid (DNA) as told by James Watson.

Watson and another scientist named Francis Crick discovered

the structure of this hereditary molecule. These two scientists

discovered that DNA was much more important than originally

thought by most of the scientists. Watson and Crick used the

findings of other scientists with their pursuit to become famous

before someone else found the answer.

James Watson was an American that went to Cambridge

University to do scientific research and experiments. He

always had this fantasy of discovering the DNA structure and

becoming famous. Watson always kept trying to work on it

and even had to report on things that he had not even been

working on. No one, it seemed, thought that DNA was

something that needed to be researched thoroughly.

Eventually, Watson became friends with Francis Crick who

shared Watson's interest in DNA. They decided to help each

other to find the answer. Watson and Crick started to build

models of what they thought the DNA structure might look like.

To do this, they needed data from other scientists.

Watson and Crick used Rosalind Franklin's X-ray work on

DNA to try to decide if DNA was helical and if so how many

helixes was its structure composed of. The first X-ray

photograph of crystalline DNA in the A form did not show

clearly that DNA was in fact helical when Franklin observed it.

When Watson and Crick created a DNA model with helixes,

Franklin was the first to object. They still believed that DNA

was helical and intended to prove it even though their model

was wrong because of other reasons as well. Watson knows

that sometimes scientists are wrong. This is good to know

because it shows what a struggle it was to figure out anything

if you do not know for sure if the information is right or wrong.

Later on, another X-ray photograph was taken of

crystalline DNA but this time in the B form. This showed a

great contrast between the B form and the A form. The B form

showed the probability that there were in fact two helixes and

forced Franklin to reevaluate her previous conclusion.

Bases were part of the DNA structure. The purines are

adenine and guanine and the pyrimidines are cytosine and

thymine. Watson began to think that a like-with-like model was

the correct arrangement of the bases. The problem with that

assumption is that purines have two rings and are bulkier than

pyrimidines. The purine-purine is bulkier than the

pyrimidines-pyrimidines and would cause bulges in the shape

of the DNA. This was not shown in the x-ray photograph so

this could not occur. The correct arrangement is

purine-pyrimidine. Rosalind Franklin's X-ray data convinced her

that the bases were at the center of the structure, and this

proved to be correct.

Watson then uses a suggestion of Jerry Donohue and

decides that there are hydrogen bonds between the bases.

The tautomeric shift is the hydrogen atoms that can go

through the changes in position. The sugar-phosphate chains

were placed along the outside of the model, as Rosalind

Franklin had said. At first, Watson and Crick decided that the

sugar-phosphate backbone should be near the center to

ensure the regularity of the DNA structure. They soon realized

that could not be. The negatively charged phosphate ions

would repel each other, so the structure was not possible.

James Watson and Francis Crick were the last people to finish a

problem that had been around for a while. I think that they used

many others and they received almost all of the credit. The other

scientist that was proved wrong about his structure of DNA should

have been told by either Crick or Watson of his mistake. They knew

of the mistake before most people and thought that they could buy a

couple more days to figure it out for themselves before he found out

he was wrong. Watson said he knew that when this scientist was

proved wrong he would work day and night to regain his former

reputation. They did not want to give Pauling time to reconfigure his

hypothesis and basically took it away from him. That is okay though.

What else are you supposed to do? I would probably do the same.

Another instance of how scientists can really be is when Watson and

Crick started to work with DNA in the first place. They knew that

someone already was working on DNA and they did not ask for

permission before beginning. Watson eventually asked him and he

said it was alright. James said he would not have stopped

experimenting anyway. Is that what scientists do? I guess it is no

different then any other profession, so it does not make me think any

less of them. Overall, I thought the book was good but a little boring

and confusing. I lost track of all the different scientists. Watson kept

using both their first and last names when talking about them and I

could not figure out who was who. I think this was a great discovery

and I now know how the scientific process works.