THE MOLECULAR BASIS OF INHERITANCE
DNA MAKES RNA MAKES PROTEIN
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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A in DNA is about equal to the percentage of G
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T in DNA is about equal to the percentage of A
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A in DNA is much greater than the percentage of T
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C in DNA is much greater than the percentage of G
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Detailed explanation-1: -Human DNA is 30.9% A and 29.4% T, 19.9% G and 19.8% C. The rule constitutes the basis of base pairs in the DNA double helix: A always pairs with T, and G always pairs with C.
Detailed explanation-2: -This is because adenine will always pair with thymine, so there will be just as many thymine bases as adenine bases. Together, adenine and thymine compose 70% of the segment. This means that 30% of the section is composed of guanine-cytosine pairs.
Detailed explanation-3: -The second parity rule was discovered in 1968. It states that, in single-stranded DNA, the number of adenine units is approximately equal to that of thymine (%A ≈ %T), and the number of cytosine units is approximately equal to that of guanine (%C ≈ %G).
Detailed explanation-4: -Thymine (T) makes up 28% of the nucleotides in a sample of DNA from an organism.
Detailed explanation-5: -According to Chargaff’s rule in a DNA molecule A = T and G = C and A + G + C + T = 100%. Here cytosine (C) is 18% hence G = 18% ∴ A + T = (100 – 36)% ∴ A + T = 64% ∴ A = 32% Q. In a double stranded DNA molecule, the percentage of cytosine is 18.