AP BIOLOGY

THE MOLECULAR BASIS OF INHERITANCE

STRUCTURE OF NUCLEIC ACIDS

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
If a researcher investigating a RNA strand discovers it contains 36% uracil, which of the following identifies the amount of cytosine?
A
14%
B
28%
C
64%
D
cannot be determined
Explanation: 

Detailed explanation-1: -Thus, thymine is the nitrogenous base which is not present in RNA.

Detailed explanation-2: -Explanation: DNA is made up of Adenine, Thymine, Guanine, and Cytosine. RNA has these same bases, except in RNA, there is no Thymine. Instead, Uracil is found.

Detailed explanation-3: -Uracil (U) is one of the four nucleotide bases in RNA, with the other three being adenine (A), cytosine (C) and guanine (G). In RNA, uracil pairs with adenine. In a DNA molecule, the nucleotide thymine (T) is used in place of uracil.

Detailed explanation-4: -Correct answer: Explanation: We can use Chargaff’s rule to find the remaining compositional percentages. Adenine always pairs with thymine, so their percentages will be equal. Cytosine always pairs with guanine, so their percentages will also be equal.

There is 1 question to complete.