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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20%
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30%
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40%
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60%
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Detailed explanation-1: -Since adenine is 20%, then thymine is 20% as well. The total of both is 40%. From 100 remains 60% which is divided equally between guanine and cytosine, so each is 30%. Uracil is not found in DNA but it will have the same percentage as thymine, i.e the RNA will have 30% uracil.
Detailed explanation-2: -A DNA molecule with 20% thymine would, barring mutations, also contain 20% thymine. So, approximately 40% of this DNA consists of A and T. That leaves 60% for G and C, and there must be equal amounts of each, so essentially 30% of each nitrogenous base.
Detailed explanation-3: -Therefore, Guanine would be 20% and total of G+C = 40% and hence A+T would be 60% that is 30% each. Hence, option C is correct answer.
Detailed explanation-4: -If 20% of the nucleotide are adenine, then 20% of the nucleotide are thymine. The remaining 60% is divided equally between cytosine and guanine; each would compose 30% of the molecule. This is known as Char gaff’s rules.
Detailed explanation-5: -Since adenine and guanine are always present in equal numbers, the percentage of adenine molecule is 30%.