c. - Answered by a verified Tutor Backbone formed by covalent bonds that connect sugar of one nucleotide to phosphate of another b. The amount of A, T, G and C in DNA varies from species to species Purines Pyrimidines 2. of _____ are equal to those of thymine and the percentages of _____ are equal to those of guanine in the DNA molecule. Given the percentage for any base in a sample, you can use simple math to find the percentage of any other base. Chargaff's Rule of Base Pairing The rules of base pairing (or nucleotide pairing) are: A with T: the purine adenine (A) always pairs with the pyrimidine thymine (T) C with G: the pyrimidine cytosine (C) always pairs with the purine guanine (G) . Chargaff's rule states that the amounts of guanine and cytosine are roughly the same, and the amounts of adenine and thymine are roughly the same but the relative amounts of G+C and A+T vary by species. If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked. Tetapi tidak semua orang tahu tentang prinsip-prinsip struktur dan â¦ Two sides held together by weak hydrogen bonds between bases c. Base pairing rules- A with T and C with G 20 III. therefore if [A]=40% then the [T] will also be 40%. B. but the relative amounts of G+C and A+T vary by species. The second of Chargaff's rules (or "Chargaff's second parity rule") is that the composition of DNA varies from one species to another; in particular in the relative amounts of A, G, T, and C bases. Yes. It helps in identifying the source of DNA. This is consistent with there not being enough space (20 Å) for two purines to fit â¦ the amount of purine=the amount of pyramidine in a given DNA â¦ (2) A + G = T + C, i.e. This is called Chargaff's rule of complementary base pairing. But this rule rule is applicable only for double stranded DNA molecule. Chargaffs rule for DNA base pairing indicates that Answer: D A+T =G+C Explanation: According to Chargaffs rule any cell in an organism should have pyrimidine and purine bases in a 1:1 ratio. If you are having trouble with Chemistry, Organic, Physics, Calculus, or Statistics, we got your back!