About purine and pyrimidine nucleotides, all are true except-
Ans. is 'c' i.e., Adenosine is a nucleotide o Two types of bases are found in nucleotides : (i) purines and (ii) pyrimidines.i) Purines : Two major purine bases found both in DNAs as well as RNAs are (i) adenine (A) and (ii) guanine (G).ii) 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 notfound in DNAs Q and thymine is not found in RNAs.Different major bases with their corresponding nucleosides and nucleotidesBaseRibonucleosideRibonucleotideAdenine (A)Guanine (G)Uracil (U)Cytosine (C)AdenosineGuanosineUridineCytidineAdenosine monophosphate (AMP)Guanosine monophosphate (GMP)Uridine monophosphate (UMP)Cytidine (Monophosphate) (CMP)BaseDeoxy ribonucleosideDeoxyribonucleotideAdenineGuanineCytosineThymineDeoxyadenosineDeoxyguanosineDeoxycytidineDeoxythymidineDeoxyadenosine monophosphate (dAMP)Deoxyguanosine monphosphate (dGMP)Deoxycytidine monophosphate (dCMP)Deoxythymidine monophosphate (dCMP)o Thus adenosine is a nucleoside (not nucleotide)Nucleoside= Nitrogenous base (purine or pyrimidine) + Pentose sugar (ribose or deoxyribose)Nucleotide= Nucleoside + phosphate group (phosphoric acid)or= Nitrogenous base + Pentose sugar + Phosphate group
Uracil is not found in DNA
Thymine is not found in RNA
Adenosine is a nucleotide
Adenine is present in both DNA and RNA
Metabolism of Purines and Pyrimidines