Urea, also called carbamide, is an organic compound with chemical formula CO(NH2)2. This amide has two amino groups joined by a carbonyl functional group. It is thus the simplest amide of carbamic acid.
Uric acid is a heterocyclic compound of carbon, nitrogen, oxygen, and hydrogen with the formula C5H4N4O3. It forms ions and salts known as urates and acid urates, such as ammonium acid urate. Uric acid is a product of the metabolic breakdown of purine nucleotides, and it is a normal component of urine. High blood concentrations of uric acid can lead to gout and are associated with other medical conditions, including diabetes and the formation of ammonium acid urate kidney stones.
The urea cycle (also known as the ornithine cycle) is a cycle of biochemical reactions that produces urea (NH2)2CO from ammonia (NH3). Animals that use this cycle, mainly amphibians and mammals, are called ureotelic.
The excretory system is a passive biological system that removes excess, unnecessary materials from the body fluids of an organism, so as to help maintain internal chemical homeostasis and prevent damage to the body. The dual function of excretory systems is the elimination of the waste products of metabolism and to drain the body of used up and broken down components in a liquid and gaseous state. In humans and other amniotes, most of these substances leave the body as urine and to some degree exhalation, mammals also expel them through sweating.
Excretion is elimination of metabolic waste, which is an essential process in all organisms. In vertebrates, this is primarily carried out by the lungs, kidneys, and skin. This is in contrast with secretion, where the substance may have specific tasks after leaving the cell. For example, placental mammals expel urine from the bladder through the urethra, which is part of the excretory system. Unicellular organisms discharge waste products directly through the surface of the cell.
Hyperammonemia is a metabolic disturbance characterised by an excess of ammonia in the blood. It is a dangerous condition that may lead to brain injury and death. It may be primary or secondary.
Allantoin is a chemical compound with formula C4H6N4O3. It is also called 5-ureidohydantoin or glyoxyldiureide. It is a diureide of glyoxylic acid. Allantoin is a major metabolic intermediate in most organisms including animals, plants and bacteria. It is produced from uric acid, which itself is a degradation product of nucleic acids, by action of urate oxidase (uricase). Allantoin also occurs as a natural mineral compound (IMA symbol Aan).
Assimilation is the process of absorption of vitamins, minerals, and other chemicals from food as part of the nutrition of an organism. In humans, this is always done with a chemical breakdown and physical breakdown. Chemical alteration of substances in the bloodstream by the liver or cellular secretions. Although a few similar compounds can be absorbed in digestion bio assimilation, the bioavailability of many compounds is dictated by this second process since both the liver and cellular secretions can be very specific in their metabolic action. This second process is where the absorbed food reaches the cells via the liver.
The Malpighian tubule system is a type of excretory and osmoregulatory system found in some insects, myriapods, arachnids and tardigrades.
Protein toxicity is the effect of the buildup of protein metabolic waste compounds, like urea, uric acid, ammonia, and creatinine. Protein toxicity has many causes, including urea cycle disorders, genetic mutations, excessive protein intake, and insufficient kidney function, such as chronic kidney disease and acute kidney injury. Symptoms of protein toxicity include unexplained vomiting and loss of appetite. Untreated protein toxicity can lead to serious complications such as seizures, encephalopathy, further kidney damage, and even death.
Glucuronic acid is a uronic acid that was first isolated from urine. It is found in many gums such as gum arabic, xanthan, and kombucha tea and is important for the metabolism of microorganisms, plants and animals.
The enzyme argininosuccinate lyase (EC 4.3.2.1, ASL, argininosuccinase; systematic name 2-(N ω-L-arginino)succinate arginine-lyase (fumarate-forming)) catalyzes the reversible breakdown of argininosuccinate:
Urine is a liquid by-product of metabolism in humans and in many other animals. In placental mammals, urine flows from the kidneys through the ureters to the urinary bladder and is ejected from the penis or vulva through the urethra during urination. In other vertebrates, urine is excreted through the cloaca.
Merriam-Webster defines chemotaxonomy as the method of biological classification based on similarities and dissimilarity in the structure of certain compounds among the organisms being classified. Advocates argue that, as proteins are more closely controlled by genes and less subjected to natural selection than the anatomical features, they are more reliable indicators of genetic relationships. The compounds studied most are proteins, amino acids, nucleic acids, peptides etc.
Microbial metabolism is the means by which a microbe obtains the energy and nutrients it needs to live and reproduce. Microbes use many different types of metabolic strategies and species can often be differentiated from each other based on metabolic characteristics. The specific metabolic properties of a microbe are the major factors in determining that microbe's ecological niche, and often allow for that microbe to be useful in industrial processes or responsible for biogeochemical cycles.
Phenylacetylglutamine is a product formed by the conjugation of phenylacetate and glutamine. It is a common metabolite that occurs naturally in human urine.
Nitrogen's effects on agriculture profoundly influence crop growth, soil fertility, and overall agricultural productivity, while also exerting significant impacts on the environment.
Osmoregulation is the active regulation of the osmotic pressure of an organism's body fluids, detected by osmoreceptors, to maintain the homeostasis of the organism's water content; that is, it maintains the fluid balance and the concentration of electrolytes to keep the body fluids from becoming too diluted or concentrated. Osmotic pressure is a measure of the tendency of water to move into one solution from another by osmosis. The higher the osmotic pressure of a solution, the more water tends to move into it. Pressure must be exerted on the hypertonic side of a selectively permeable membrane to prevent diffusion of water by osmosis from the side containing pure water.
The rock dove, Columbia livia, has a number of special adaptations for regulating water uptake and loss.
Carbamoyl phosphate synthetase III is one of the three isoforms of the carbamoyl phosphate synthetase, an enzyme that catalyzes the active production of carbamoyl phosphate in many organisms.
