a1.2.15 - chargaff's data on the relative amounts of pyrimidine and purine bases

Question 1

describe the implications of Chargaff’s data that showed a 1:1 ratio of purine to pyrimidine in a sample of DNA.

Answer 1

• chargaff’s research revealed the percentage of each base (A, T, C, G) found in different species DNA. he determined that there are equal numbers of A and T bases and G and C bases in a DNA sample, resulting in a 1:1 ratio of purines to pyrimidines in DNA.
• chargaff did not use inductive reasoning to then infer the pattern that A binds to T and C binds to G. the complementary base pairing rule was inferred by Watson and Crick.

Question 2

explain the role of falsifiability in determining the structure and function of DNA.

Answer 2

• to falsify means that a statement, theory or hypothesis is proven to be wrong.
• because he found that the amount of one base wasn’t equal to the amount of the three other bases , Chargaff’s data falsified the earlier hypothesis that DNA had a tetranucleotide structure. in this proposed model of DNA, the four bases occur in equal amounts in four strands arranged with the bases facing outward.