CHEMISTRY GLOSSARY

keratin    →   keratin

Keratin is an insoluble protein that is the major constituent of the outer layer of the skin, nails, and hair. It contains greater amounts of amino acid called cystine.

Lewis, Gilbert N.    →   Lewis, Gilbert N.

Gilbert Newton Lewis (1875-1946) is an American chemist whose theory of the electron pair fostered understanding of the covalent bond and extended the concept of acids and bases.

lipase    →   lipaza

Lipase is an enzyme, secreted by the pancreas and the glands of the small intestine that breaks down fats into glycerol and fatty acids during digestion.

Contat-Gockel’s valve    →   Contat-Gockelov ventil

Contat-Göckel’s valve is used for maintenance of inert atmosphere in a flask. The valve is filled with a saturated solution of sodium bicarbonate (NaHCO₃) so that the end of the tube is covered. Solution inside the valve keeps the flask contents away from the oxygen influence from air. If low pressure is created inside the flask (when the flask is cooled), the solution will penetrate inside it from funnel and in a reaction with acid CO₂ is generated which fills up the flask.

Solution from the funnel will keep penetrating until CO₂ pressure in the flask is equalised with the outer pressure.

copolymer    →   kopolimer

Copolymers are also known as heteropolymers. They are made from two (or more) different monomers, which usually undergo a condensation reaction with the elimination of a simple molecule, such as ammonia or water. A typical example is the condensation of 1,6-diaminohexane (hexamethylenediamine) with hexanedioic acid (adipic acid) to form nylon 6,6.

The properties of a polymeric plastic can most easily be modified if it is a copolymer of two or more different monomers, e.g. acrylonitrile-butadiene-styrene copolymer (ABS). Varying the proportions of the component monomers can preselect its properties.

cysteine    →   cistein

Cysteine is neutral amino acids with polar side chains. Because of its high reactivity, the thiol group of cysteine has numerous biological functions. It serves as a potent nucleophile and metal ligand (particularly for iron and zinc), but is best known for its ability to form disulfide bonds, which often make an important contribution to the stability of extracellular proteins. Cysteine is a non-essential amino acid, which means that it is biosynthesized in humans.

• Abbreviations: Cys, C
• IUPAC name: 2-amino-3-sulfanylpropanoic acid
• Molecular formula: C₃H₇NO₂S
• Molecular weight: 121.16 g/mol

litmus paper    →   lakmus-papir

Litmus paper is an unsized paper treated with litmus for the use as an acid-base indicator, in an acid it turns red, and in a base it turns blue.

mercaptans    →   merkaptani

Mercaptans are a traditional term abandoned by IUPAC, synonymous with thiols, a sulfur-containing organic compound with the general formula R-SH where R is any radical. This term is still widely used.

methanoate    →   metaonat

Methanoate (formate) is a salt of methanic (formic) carboxyl acid.

Millon’s reaction    →   Millonova reakcija

Millon’s reaction is used for testing proteins by the appearance of red colour which the proteins give by reacting with a solution of mercury in nitric acid.