Chapter 21, Problem 31CQ

(a)

Summary Introduction

To determine: The number of ATP equivalents that are consumed during the reactions of urea cycle.

Concept introduction:

The urea cycle involves the production of urea through many biochemical reactions. Five enzymes are involved in the urea cycle, namely ornithine transcarbamylase (OTC), carbamoyl-phosphate synthetase 1 (CPS1), arginase 1 (ARG1), argininosuccinate synthetase (ASS1), argininosuccinate lyase (ASL). The urea cycle involves the conversion of excess nitrogen generated from the amino acid breakdown in the proteins into an excretable form called urea.

(b)

Summary Introduction

To explain: The operation of the urea cycle that generates more ATP than it consumes.

Concept introduction:

The urea cycle involves the production of urea through many biochemical reactions. Five enzymes are involved in the urea cycle, namely ornithine transcarbamylase (OTC), carbamoyl-phosphate synthetase 1 (CPS1), arginase 1 (ARG1), argininosuccinate synthetase (ASS1), argininosuccinate lyase (ASL). The urea cycle involves the conversion of excess nitrogen generated from the amino acid breakdown in the proteins into an excretable form called urea.