Not present in DNA ?

Ans. is 'a' i.e., Uracil 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 e and thymine is not found in RNAs. Different major bases with their corresponding nucleosides and nucleotides Base Ribonucleoside Ribonucleotide Adenine (A) Adenosine Adenosine monophosphate (AMP) Guanine (G) Guanosine Guanosine monophosphate (GMP) Uracil (U) Uridine Uridine monophosphate (UMP) Cytosine (C) Cytidine Cytidine (Monophosphate) (CMP) Base Deoxyribonucleoside Deoxyribonucleotide Adenine Deoxyadenosine Deoxyadenosine monophosphate (dAMP) Guanine Deoxyguanosine Deoxyguanosine monphosphate (dGMP) Cytosine Deoxycytidine Deoxycytidine monophosphate (dCMP) Thymine Deoxythymidine Deoxythymidine monophosphate (dCMP)