AP BIOLOGY

Detailed explanation-1: -Erwin chargaff gave then rule that demonstrate the nitrogenous component of the DNA double helix and such rule is called as chargaff’s rule. It states that the DNA of all the organism have equal number of purine and pyrimidine i.e., in 1 : 1 ratio.

Detailed explanation-2: -Erwin Chargaff found that in DNA, the ratios of adenine (A) to thymine (T) and guanine (G) to cytosine (C) are equal. This parity is obvious in the final DNA structure.

Detailed explanation-3: -This sentence refers to the work of Erwin Chargaff, a biochemist at Columbia University. In the late 1940s, Chargaff analyzed the proportions of the four different types of base molecules in DNA, and found that DNA always contains equal amounts of guanine and cytosine, and equal amounts of adenine and thymine.

Detailed explanation-4: -Key conclusions from Erwin Chargaff’s work are now known as Chargaff’s rules. The first and best known achievement was to show that in natural DNA the number of guanine units equals the number of cytosine units and the number of adenine units equals the number of thymine units.

Detailed explanation-5: -In 1950, Erwin Chargaff published a paper stating that in DNA of any given species, the ratio of adenine to thymine is equal, as is the ratio of cytosine to guanine. This is known as Chargaff’s ratios and it was a crucial clue that helped solve the structure of DNA.