Purine and pyrimidine nucleotides serve as monomeric units of the nucleic acid polymers DNA and RNA. Mentioned below are some of the statements with respect to the de novo synthesis of nucleotides. Which one of the following statements is INCORRECT?
1
Biosynthesis of both purine and pyrimidine nucleotides begin with ribose-5-phosphate and purine or pyrimidine rings are built on it.
2
The first purine nucleotide biosynthesized by de novo pathway is inosinic acid or inosine-monophosphate.
3
The first pyrimidine nucleotide biosynthesized by de novo pathway is orotidylic acid or orotidine monophosphate.
4
Thymidylate or TMP is synthesized as deoxy-TMP from deoxy-UMP by thymidylate synthetase.
5
Question Not Attempted