BIOLOGY
NUCLEIC ACIDS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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If there is 23% Guanine in a DNA molecule, how much Uracil exists in the same molecule?
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23%
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46%
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54%
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27%
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0%
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Explanation:
Detailed explanation-1: -The correct answer: A DNA molecule with 24% guanine would have 26% adenine.
Detailed explanation-2: -DNA bases bond in pairs with Thymine to Adenine and Guanine to Cytosine. For every one Thymine there will be one Adenine. So, 23% Thymine would mean that there is also 23% Guanine. Guanine would equal 54%/2 or 27%.
Detailed explanation-3: -If a cell contains 20% guanine, it will contain 30% adenine. According to Chargaff’s rules, %G = %C and %A = %T. The bases G and C are complementary and are always equal in amount in double-stranded DNA.
Detailed explanation-4: -Therefore the base percentage of GC is 54% in the whole DNA sequence.
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