Question

Different type of urine excretes by organisms and their functions

Answer 1

• Metabolism of carbohydrates and fats produces CO2and H2O which are easy to remove. They are effectively removed through lungs (expired air), skin (sweat) or kidneys (urine).
• Other excretory products such as bile pigments (formed by the breakdown of RBCs), drugs etc. are removed in liver.
• Metabolism of proteins produces nitrogenous wastes such as ammonia, which is the basic nitrogenous catabolites of protein, formed by breakdown of amino acids is finally removed from Kidney.
• Depending upon the form in which nitrogenous waste is excreted from the body, the organisms are grouped as under into three categories:

Ammonotelic, Uricotelic and Ureotelic

1. Amminotelic organism

• Those animals which excrete their nitrogenous waste in the form of ammonia are known as ammonotelic.
• Ammonia is highly soluble in water with which it forms ammonium hydroxide (NH4OH) which can damage cells directly by its alkaline caustic action.
• Excretion of ammonia requires large amounts of water, so that more water loss from the body. That is why such a mode is suitable for aquatic organisms which have a constant access to water.
• Ammonia is the first metabolic waste product of protein metabolism and no energy is required to produce ammonia.
• Examples: All aquatic invertebrates, bony fishes and aquatic amphibians are amminotelic organisms.

2. Uricotelic organism

• Those animals which excrete their nitrogenous waste mainly in the form of uric acid and urates are known as uricotelic.
• The phenomenon is known as uricotelism.
• Elimination of uric acid requires lesser amount of water, comparatively less soluble in water and is less toxic as compared to ammonia.
• Examples: All terrestrial animals like insects, reptiles, and birds excrete uric acid as nitrogenious wastes

3. Ureotelic organism

• Those animals that excrete their nitrogenous waste mainly in the form of urea are known as ureotelic and the phenomenon is known as ureotelism.
• Urea can be stored in body for considerable periods of time, and is least toxic. It is eliminated in the form of urine.
• Examples: Ureotelism is exhibited by semi-terrestrial animals, e.g. adult amphibians and mammals