Chapter 23, Problem 7E

(a)

Summary Introduction

To determine: The cost of ATP equivalent to synthesize IMP.

Concept introduction: Nucleotides are phosphate esters of a pentose in which a purine or pyrimidine base is linked to C1 of the sugar. Nucleotides are the building blocks of nucleic acids. There are two pathways of nucleotide biosynthesis, namely, de novo pathway and salvage pathway.

In salvage synthesis, the nitrogenous base is attached with ribose sugar in the form of 5-phosphoribosyl-1-pyrophosphate; in de novo synthesis, the nitrogenous base synthesizes from a simple starting material and ATP is required.

(b)

Summary Introduction

To determine: The cost of ATP equivalent to synthesize AMP.

Concept introduction: Nucleotides are phosphate esters of a pentose in which a purine or pyrimidine base is linked to C1 of the sugar. Nucleotides are the building blocks of nucleic acid. There are two pathways of nucleotide biosynthesis, namely, de novo pathway and salvage pathway. In salvage synthesis, the nitrogenous base is attached with ribose sugar in the form of 5-phosphoribosyl-1-pyrophosphate. On the other hand, in the de novo synthesis, the nitrogenous base synthesizes from a simple starting material and ATP is required.

(c)

Summary Introduction

To determine: The cost of ATP equivalent to synthesize CTP.

Concept introduction: There are two pathways of nucleotide biosynthesis, namely, de novo pathway and salvage pathway. In salvage pathway of nucleotide synthesis, the nitrogenous base is attached with ribose sugar in the form of 5-phosphoribosyl-1-pyrophosphate. On the other hand, in de novo synthesis, the nitrogenous base synthesizes from a simple starting material and ATP is required.