AP BIOLOGY

THE MOLECULAR BASIS OF INHERITANCE

STRUCTURE OF NUCLEIC ACIDS

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
Which nitrogen bases are considered purines and which are considered pyrimidines?
A
A and T are pyrimidines, G, U, and C are purines
B
A and G are purines, T, C, and U are pyrimidines
C
A, U, and C are purines, T and G are pyrimidines
D
A and G are pyrimidines, T, U, and C are purines
Explanation: 

Detailed explanation-1: -Purines (adenine and guanine) are two-carbon nitrogen ring bases while pyrimidines (cytosine and thymine) are one-carbon nitrogen ring bases.

Detailed explanation-2: -The purines in DNA are adenine and guanine, the same as in RNA. The pyrimidines in DNA are cytosine and thymine; in RNA, they are cytosine and uracil.

Detailed explanation-3: -Adenine (A) and guanine (G) are purines, and cytosine (C), thymine (T), and uracil (U) are pyrimidines.

Detailed explanation-4: -DNA base pair. Under normal circumstances, the nitrogen-containing bases adenine (A) and thymine (T) pair together, and cytosine (C) and guanine (G) pair together. The binding of these base pairs forms the structure of DNA .

Detailed explanation-5: -Final answer: The nitrogenous base guanine/G is not a pyrimidine.

There is 1 question to complete.