OBJECTIVE LIFE SCIENCE
MOLECULAR BIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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The amount of adenine and thymine is equal to the amount of guanine and cytosine
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The amount of adenine and guanine is equal to the amount of thymine and cytosine
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The amount of adenine and uracil is equal to the amount of guanine and cytosine
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The amount of adenine and guanine is equal to the amount of uracil and cytosine
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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: -Answer and Explanation: True. In all celled organisms, genomic DNA is double-stranded and the pairs purine-pyrimidines are always: Adenine (A, a purine)-Thymine (T, a pyrimidine), and Guanine (G, a purine)-Cytosine (C, a pyrimidine). Consequently, in any given dsDNA molecule the amount of A=T and G=C.
Detailed explanation-3: -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.