THE MOLECULAR BASIS OF INHERITANCE
STRUCTURE OF NUCLEIC ACIDS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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10
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20
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40
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80
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Impossible to tell from the information given
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Detailed explanation-1: -In the DNA structure, adenine base always pairs with thymine and cytosine always pairs with guanine. If 10% of the bases in a DNA are adenine, 10% of this DNA molecule must be thymine. The remaining 80% will be made up of 40% cytosine and 40% guanine since the bases pair with each other leaving a ratio of 1:4.
Detailed explanation-2: -Answer and Explanation: A double-stranded DNA molecule with 20% thymine would contain 30% guanine. Erwin Chargaff determined that species have almost equal levels of adenine and thymine, and guanine and cytosine.
Detailed explanation-3: -Since cytosine and guanine are present in equal amounts, we can simply divide their sum by 2. The final composition is 22% adenine, 22% thymine, 28% cytosine, and 28% guanine.
Detailed explanation-4: -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.