LABORATORY REVIEW
MOLECULAR BIOLOGY
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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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80%
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Detailed explanation-1: -30% of guanine and 30% of cytosine, because their amounts are equal in the DNA stand.
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: -The remaining 60% represents both G + C molecule. Since cytosine and guanine are always present in equal numbers, the percentage of guanine molecule is 30%.
Detailed explanation-4: -So, for this DNA sequence, C + G = 60%. The remaining 40% of the sequence must consist of A-T pairs (adenine-thymine). Therefore, 20% of the sequence is made up of adenine, and 20% of the sequence is made up of thymine.