• Add PRPP + amino acids + ATP + CO2 + more Makes a nucleotide

• 2 different strategies

Pyrimidine rings are formed first and then are attached to activated ribose (PRPP) Make UTP and then CTP Ribonucleotides that can be used to make RNA Then UTP can make TMP and CTP can make dCTP Deoxyribonucleotides that can be used to make DNA

Purine rings are formed piece by piece right on the ribose-based structure (PRPP) They first make the intermediate IMP Then go to ATP and GTP Ribonucleotides that can be made into RNA ATP can make dATP and GTP can make dGTP Deoxyribonucleotides that can be used to make DNA