Metabolic waste - wikipedia Metabolic waste This article is about unwanted substances expelled from living organisms. For similar terms with different meanings, see Waste ( disambiguation ). This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( December 2009 ) Metabolic wastes or excretes are substances left over from metabolic processes ( such as cellular respiration ) which can not be used by the organism ( they are surplus or toxic ), and must therefore be excreted. This includes nitrogen compounds, water, CO, phosphates, sulfates, etc. Animals treat these compounds as excretes. Plants have chemical `` machinery '' which transforms some of them ( primarily the nitrogen compounds ) into useful substances, and it has been shown by Brian J. Ford that abscised leaves also carry wastes away from the parent plant. In this way, Ford argues that the shed leaf acts as an excretory ( an organ carrying away excretory products ). All the metabolic wastes are excreted in a form of water solutes through the excretory organs ( nephridia, Malpighian tubules, kidneys ), with the exception of CO, which is excreted together with the water vapor throughout the lungs. The elimination of these compounds enables the chemical homeostasis of the organism. Contents 1 Nitrogen wastes 1.1 Ammonotelism 1.2 Ureotelism 1.3 Uricotelism 2 Water and gases 3 Solids 4 See also 5 References Nitrogen wastes Further information : Urea § Physiology, and Urea cycle The nitrogen compounds through which excess nitrogen is eliminated from organisms are called nitrogenous wastes ( / naɪˈtrɒdʒɪnəs / ) or nitrogen wastes. They are ammonia, urea, uric acid, and creatinine. All of these substances are produced from protein metabolism. In many animals, the urine is the main route of excretion for such wastes ; in some, the feces is. Ammonotelism Ammonotelism is the excretion of ammonia and ammonium ions. Ammonia ( NH ) forms with the oxidation of amino groups. ( - NH ), which are removed from the proteins when they convert into carbohydrates. It is a very toxic substance to tissues and extremely soluble in water. Only one nitrogen atom is removed with it. A lot of water is needed for the excretion of ammonia, about 0.5 L of water is needed per 1 g of nitrogen to maintain ammonia levels in the excretory fluid below the level in body fluids to prevent toxicity. Thus, the marine organisms excrete ammonia directly into the water and are called ammonotelic. Ammonotelic animals include protozoans, crustaceans, platyhelminths, cnidarians, poriferans, echinoderms, and other aquatic invertebrates. Ureotelism The excretion of urea is called ureotelism. Land animals, mainly amphibians and mammals, convert ammonia into urea, a process which occurs in the liver and kidney. These animals are called ureotelic. Urea is a less toxic compound than ammonia ; two nitrogen atoms are eliminated through it and less water is needed for its excretion. It requires 0.05 L of water to excrete 1 g of nitrogen, approximately only 10 % of that required in ammonotelic organisms. Uricotelism Uricotelism is the ridding of excess nitrogen using uric acid. This method is used by birds and diapsids, insects, lizards, and snakes, and these animals are called uricotelic. Uric acid is less toxic than ammonia or urea. It contains four nitrogen atoms and only a small amount of water ( about 0.001 L per 1 g of nitrogen ) is needed for its excretion. Uric acid is the least soluble in water and can be stored in cells and body tissues without toxic effects. A single molecule of uric acid can remove four atoms of nitrogen making uricotelism more efficient than ammonotelism or ureotelism. Uricotelic organisms typically have white pasty excreta. Some mammals including humans excrete uric acid as a component of their urine but it is only a small amount. Water and gases These compounds form during the catabolism of carbohydrates and lipids in condensation reactions, and in some other metabolic reactions of the amino acids. Oxygen is produced by plants and some bacteria in photosynthesis, while CO is a waste product of all animals and plants. Nitrogen gases are produced by denitrifying bacteria and as a waste product, and bacteria for decaying yield ammonia, as do most invertebrates and vertebrates. Water is the only liquid waste from animals and photosynthesizing plants. Solids Nitrates and nitrites are wastes produced by nitrifying bacteria, just as sulfur and sulfates are produced by sulfur - reducing bacteria and sulfate - reducing bacteria. Insoluble iron waste can be made by iron bacteria by using soluble forms. In plants, resins, fats, waxes, and complex organic chemicals are exuded from plants, e.g., the latex from rubber trees and milkweeds. Solid waste products may be manufactured as organic pigments derived from breakdown of pigments like hemoglobin, and inorganic salts like carbonates, bicarbonates, and phosphate, whether in ionic or molecular form, are excreted as solids. Animals dispose of solid waste as feces. See also Ammonia poisoning Deamination References Jump up ^ Chris M. Wood ; R.S. Munger ; D.P. Toews ( 1989 ). `` Ammonia, urea, and H distribution and the evolution of ureotelism in amphibians '' ( PDF ). Journal of Experimental Biology. 144 : 215 -- 233. ^ Jump up to : S. Sreekumar ( 2010 ). Basic Physiology. PHI Learning Pvt. Ltd. p. 180 -- 181. ISBN 9788120341074. ^ Jump up to : `` excretion. '' Encyclopædia Britannica. Encyclopædia Britannica Ultimate Reference Suite. Chicago : Encyclopædia Britannica, 2010. Metabolism portal Retrieved from `` https://en.wikipedia.org/w/index.php?title=Metabolic_waste&oldid=839116598 '' Categories : Excretion Metabolism Waste Hidden categories : Articles needing additional references from December 2009 All articles needing additional references All articles with unsourced statements Articles with unsourced statements from July 2016 Talk Contents About Wikipedia Català Македонски Edit links This page was last edited on 1 May 2018, at 10 : 54. Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia ® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. About Wikipedia

Question: nitrogenous wastes may be produced as a result of the metabolism of
Answer: protein