AP BIOLOGY

Detailed explanation-1: -Chargaff’s rules states that DNA from any cell of all organisms should have a 1:1 ratio of pyrimidine and purine bases and, more specifically, that the amount of guanine is equal to cytosine and the amount of adenine is equal to thymine.

Detailed explanation-2: -Adenine always pairs with thymine, so their percentages will be equal. Cytosine always pairs with guanine, so their percentages will also be equal. The sum of all four percentages must equal 100%. We know that the sample is 22% adenine; this tells us it is also 22% thymine.

Detailed explanation-3: -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-4: -Chargaff’s rule states that the amount of adenine (A) is equal to that of thymine (T) and the amount of guanine is equal to that of cytosine (C) in an organism.

Detailed explanation-5: -The chemical structures of Thymine and Cytosine are smaller, while those of Adenine and Guanine are larger. Size and structure of the specific nucleotides cause Adenine and Thymine to always pair together while Cytosine and Guanine always pair together. Therefore the two strands of DNA are considered complimentary.