Describe the various nitrogenous waste products.

Explanation

Nitrogenous waste products : The breakdown of animal proteins and nucleic acids produce following nitrogenous waste products excreted in the animals.
1. Ammonia: It is formed by the deamination of amino acids during protein metabolism. Ammonia is highly toxic. It is highly soluble in water and is quickly eliminated in surrounding water by aquatic animals e.g. Hydra, Protozoans. The process of excretion of ammonia is called Ammonotelism and such animals who excrete ammonia are called Ammonotelic.
2. Urea : It is less toxic than ammonia. Most mammals, fishes and amphibians excrete their nitrogenous waste products in the form of urea. Process of excretion of urea is called ureotelism and such animals are called ureotelic.
3. Amino acid : In certain animals like molluscs and echinoderms the excess of amino acids are removed as such without undergoing any change. Such animals are called aminotelic and the process is called Aminotelism.
4. Uric acid : Reptiles and birds excrete uric acid and are called uricotelic.
5. Other nitrogenous waste products : Allantion and allantoic acid are other nitrogenous excretory products. These are insoluble in water and used during embryonic development by amniotes with shelled eggs.
There are certain other nitrogenous waste products such as guanine and adenine from nucleic acid break down and creatine from the creatine phosphate of muscles that are excreted along with other nitrogenous waste products in the urine. The reason for different excretory products is that the animals live in different environments.