Question
Which of the following are DNA Pyrimidine bases?
A. Adenine and Guanine
B. Guanine and Cytosine
C. Cytosine and Adenine
D. Thymine and Cytosine
Show Answer
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Correct Answer » D
Explanation
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In DNA and RNA, Pyrimidine bases form hydrogen bonds with their complementary purines.
Thus, in DNA, the purines adenine (A) and guanine (G) pair up with the pyrimidines thymine (T) and cytosine (C), respectively.
In RNA, the complement of adenine (A) is uracil (U) instead of thymine (T), so the pairs that form are adenine: uracil and guanine: cytosine.
- Two types of bases are found in nucleotides : (i) purines and (ii) pyrimidines.
- Purines: Two major purine bases found both in DNAs as well as RNAs are (i) adenine (A) and (ii) guanine (G).
- Pyrimidines: Three major pyrimidine bases are (i) cytosine (C), (ii) Uracil (U) and (iii) Thymine (T). Cytosine and uracil are found in RNAs and cytosine and thymine are found in DNAs. Uracil is not found in DNAs Q and thymine is not found in RNAs.
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