This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of Purines and Pyrimidines, Subject name: Biochemistry
Which of the follow ing is not a pyrimidine - 
Select and explain. 
A. Uracil, B. Thymine, C. Adenine, D. Cytosine
C: Adenine
Answer: C: Adenine 
Explanation: Ans. is 'c' i.e., Adenine o Two types of bases are found in nucleotides : (i) purines and (ii) pyrimidines.Purines : Tw o 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 DNAsQ and thymine is notfound in RNAs.