Chapter 18, Problem 16P

(a)

Summary Introduction

To determine: The atom of urea in which the isotope will be found.

Introduction:

The breakdown of nitrogenous compounds produces crystalline compounds which is colorless and is known as urea. The ammonia is the most common form of nitrogenous waste. It is mostly found in mammals’ urine.

(b)

Summary Introduction

To determine: The atom of succinate in which the isotope will be found.

Introduction:

The metabolic pathway in humans includes the succinate in many of the reactions which also involves the enzyme succinate dehydrogenase. It is also called as the Ester or salt form of succinic acid.

(c)

Summary Introduction

To determine: The atom of arginine in which the isotope will be found.

Introduction:

Arginine is one of the most essential amino acid. The person who is on diet lacks arginine in the urea cycle, so there will be no conversion of ammonia to urea. Arginine plays an important role in urea formation.

(d)

Summary Introduction

To determine: The atom of citrulline in which the isotope will be found.

Introduction:

Citrulline is the amino acid which aids in the flow of blood in the body. It is made in the body. Citrulline maintains the health of heart and body by improving the flow of blood.

(e)

Summary Introduction

To determine: The atom of ornithine in which the isotope will be found.

Introduction:

Ornithine is one of the amino acid which can replace arginine because ornithine is proteogenic and it can easily be converted into arginine through urea cycle.  This conversion removes the toxicity which is due to the accumulation in the body.

(f)

Summary Introduction

To determine: The atom of aspartate in which the isotope will be found.

Introduction:

Aspartate is the amino acid which is salt or ester of aspartic acid. Similarly, succinate is salt or ester of succinic acid. It plays a vital role in the cycle of urea.