BIOMOLECULES AND ENZYMES

Detailed explanation-1: -While the ratios of adenine and thiamine are the same. This rule was named after Erwin Chargaff, who discovered it in 1950. According to this model, the percentage of nitrogenous base pairs is equal to the percentage of double-stranded DNA. This is known as the first parity rule.

Detailed explanation-2: -Chargaff’s rules state that in the DNA of any species and any organism, the amount of guanine should be equal to the amount of cytosine and the amount of adenine should be equal to the amount of thymine. Further a 1:1 stoichiometric ratio of purine and pyrimidine bases (i.e., A+G=T+C ) should exist.

Detailed explanation-3: -Rule 2. In 1947 Chargaff showed that the composition of DNA, in terms of the relative amounts of the A, C, G and T bases, varied from one species to another. This molecular diversity added evidence that DNA could be the genetic material.

Detailed explanation-4: -Chargaff’s rule is not applicable for single-stranded DNA/RNA as there is no complementary base pairing.

Detailed explanation-5: -Chargaff’s observation with respect to DNA molecule structure is as follows: (i) Chargaff analysed the DNA of different species, determining its composition of A(Adenine), T(thymine), C(cytosine)and G (guanine) bases. (ii) A, T, C and G were not found in equal quantities.