BIOMOLECULES AND ENZYMES

BIOLOGY

NUCLEIC ACIDS

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Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]

A piece of DNA was analysed and 15% of its nucleotides were adenine. What percentage would be uracil?

A	0
B	15%
C	30%
D	35%

Explanation:

Detailed explanation-1: -A: The correct answer is option 2 The segment with 24%C content.

Detailed explanation-2: -Answer and Explanation: If a DNA sample were composed of 15% adenine then there would also be 15% thymine according to Chargaff’s rules. Chargaff’s rules explained that adenine always pairs with thymine and cytosine always pairs with guanine in a DNA molecule.

Detailed explanation-3: -If 15% of the nucleotides in a DNA molecule contain guanine, what percentage of the nucleotides contain each of the other three bases? Explain your reasoning. Total will be 100%. So if 15% is Guanine then Cytosine has to be 15% (because they base pair with each other).

Detailed explanation-4: -Correct answer: Together, adenine and thymine compose 70% of the segment. This means that 30% of the section is composed of guanine-cytosine pairs. Since these two bases will be equal in quantity, 15% of the DNA section will be cytosine bases.

Detailed explanation-5: -So since they have asked only regarding the uracil, We can say that it is only 15%.

There is 1 question to complete.