The history of finding DNA

First Part: The way DNA identified as hereditary material
                1. Friedrich Misescher, a Swiss biochemist, first investigated nuclein, now known as NDA.
                2. Joachim hammerling, a Danish biologist, conducted a series experiments using Acetabularia, a one-celled alga, to raise a hypothesis that the hereditary imformation is in the nucleus.
                3. In 1952, Afred Hershey and Martha Chase conducted experiments using a virus(T2) to prove that DNA was the hereditary material.

Second Part: The finding of DNA structure
                1. In 1949, Erwin Chargaff found that the proportion of adenine(A) is equal to that of thymine(T), and the proportion of guanine(G) is equal to that of cytosine(C). Also, total amount of purines equals the total amount of pyrimidines. (This discover helps solve the mystery about hte stucture of DNA)
                2. James Watson and Francis Crick built their famous model of the double-helix structure of DNA in 1953. (information provide by Maurice Wikins and Rosanlind Franklin)
                3. Rosanlind Franklin's x-ray crstallography technic sucessfully produced a clear x-ray diffraction pattern that suggested that DNA is helical in nature.

New Terms:
1. Nucleotides: molecules that consist of a five-carbon sugar(deoxyribose or ribose) with a nitrogenous base attached to 1' carbon and a phosphate group attached to 5' carbon.

Properties of DNA
1. antiparallel(parallel but running in opposite directions)
2. complementary base pairing
3. diameter of DNA is constant at 2nm