Difference Between Urea and Urine

尿素和Urine

There are differences between urea and urine though both are considered as the nitrogenous waste products that are excreted through the urinary system in animals.Metabolismofamino acids and nucleic acids导致nitrogenous wastes. When these acids are metabolized,ammoniais formed as the immediate by-product, which is quite toxic to cells and should be excreted from the body. Creatures likebony fishand many aquaticinvertebratesexcrete their nitrogenous waste directly as ammonia. However, inmammals, amphibiansandcartilaginous fish, ammonia is quickly converted into urea by their liver and excreted as urine through the excretory system. Urea is less toxic when compared to ammonia. Birds and terrestrial reptiles excrete their nitrogenous waste in the form ofuric acid. Though the production of uric acid involved more energy, it conserves a lot of water.

What is Urea?

Urea was first found and separated from human urine in 1773 byH. M. Rouelle. Urea is considered as the major organic component of humans. It is produced at the initial stage in theliveras a result of amino acid metabolism. Initially formed ammonia is first converted into urea in the liver cells and the formed urea is travelled through the blood stream tokidneys. In the kidney, urea is filtered out from the blood and excreted with urine through theurethra. Since, urea is synthesized as a result of amino acid metabolism, the amount of urea in the urine reflects the amount of protein degradation. A molecule of urea has two -NH2 groups connected via carbonyl (C=O) group, resulting the chemical formula of CO(NH₂)₂. Urea is widely used as a fertilizer, which provides氮to plants. In addition, it is also used a raw material in certain chemical industries like resins, pharmaceuticals, etc.

What is Urine?

Only mammals, amphibians and cartilaginous fish excrete their nitrogenous waste in the form of Urine. Urine is produced in the kidneys by a process called urination. Urine is composed of mainly water (about 95%) and certain other water soluble organic and inorganic compounds. The main organic compounds present in the urine include urea, uric acid,creatinine, amino acid derivatives (hippurate), urochromes (formed as a result of hemoglobin degradation), hormones (catecholamines, steroids andserotonin),glucose, ketone bodies,proteinsetc. The major inorganic components present in the urine are the cations (Na⁺, K⁺、钙²⁺, Mg₂₊, and NH⁴⁺) and anions (Cl^–, SO₄^2-, and HPO₄^2-). When the total ion concentration is considered, Na⁺and Cl^–represents two third of all electrolytes in urine.

An adult human usually produce 0.5 to 2.0 L of urine per day. The composition of the urine highly depends on the composition of diets and the amount of water intake. The urine composition and its appearance are used to identify certain diseases. For example, presence of high levels of glucose and ketone bodies can be used to diagnosediabetes mellitus. In addition, presence or absence of hCG (chorionic gonadotropin) in urine can be used for pregnancy tests.

What is the difference between Urea and Urine?

• Urea is first produced in the liver through the metabolism of nucleic acids and amino acids. However, urine is produced in the kidneys through the urination.

• Urea is the main organic component in urine.

• Urea is a single substance, but urine is a mixture of many substances.

• Urea can be found as a solid, but urine exists as a liquid.

• The amount of urea in the urine reflects the protein degradation in the body.