Final answer:
The molecule directly formed by the pyrimidine synthesis pathway is uridylate. The pyrimidine synthesis pathway begins with the combination of carbon dioxide and ammonia to form carbamoyl phosphate, which then combines with aspartate to form carbamoyl aspartate. Dihydroorotate is formed from carbamoyl aspartate, which is then converted to orotic acid and attached to ribose to yield orotidylic acid. Orotidylate is then decarboxylated to form uridylate.
Step-by-step explanation:
The molecule directly formed by the pyrimidine synthesis pathway is uridylate (UMP). In this pathway, carbamoyl phosphate combines with aspartate to form carbamoyl aspartate, which eventually leads to the formation of dihydroorotate. This is then oxidized to orotic acid which, when attached to ribose, yields orotidylic acid (orotidine 5'-phosphate). Finally, orotidylate is decarboxylated to form uridylate (UMP). Uridylate serves as a precursor for the other pyrimidine nucleotides, such as cytidine monophosphate (CMP) and thymidine monophosphate (TMP).