Biochemistry Definitions and glossary HZ

Chemistry terms within the framework of the study of the Laigret petroleum process. Definitions by Thierry Saint Germès, November 30, 2008.
Biochemistry definitions from A to G
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halogen: (Gr. Hals, halos, salt, and gennan, lead) Name given by Berzelius to chlorine family-metals (fluorine, chlorine, bromine, iodine), which can form salts with metals.

Oil : Product of mineral, animal or vegetable origin, fluid at ordinary temperature and constituted, in the first case, by heavy hydrocarbons, in the last two, by a mixture of mixed glycerides.

hydrocarbon: Synonymous with hydrogen carbide.

hydrolysis: Acid-base reaction between water and another body. Salts of a weak acid or base undergo, on contact with water, a limited hydrolysis, which releases the corresponding acid and base.

hydroxide: Combination of water and an oxide. (The hydroxides have a constitutive formula containing a metal [or a radical taking its place] joined to one or more hydroxyls -OH; thus sodium hydroxide NaOH and lime Ca (OH) 2.

hydroxyl: Univalent radical -OH, found in water, hydroxides, oxacids, alcohols, etc.


iodine: (gr. iodines, violet) Chemical element 53, atomic mass I = 126,9045, was discovered by Courtois in 1811. It is a gray-black solid, in the metallic state, crystallized in orthorombic flakes of odor irritating.

iodide: Combination of iodine with a simple or compound body.

Hydrogen ion: Hydrogen atom having lost its electron and reduced to its proton. The properties of acids in aqueous solution are due to the presence of its ions.


lactic: Said of an acid-alcohol CH3-CHOH-CO2H, which is found in whey, in a large number of plants, in various animal organs, etc.

lipase: (gr. Lipos, fat). Enzyme that hydrolyzes high molecular weight fatty acid esters.

lipolysis: Destruction of fat.

lugol: strong iodine solution to 1 percent of the codex.

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Marinating: Operation of leaving a body in a liquid in an open vessel, to extract those parts which are soluble.

Manne: Common name for various edible and sweet formations, of powdery consistency, which quickly appear in arid places. (Mannes are usually exudations produced by woody plants in reaction to the bite of a homopterous insect.

Pressure gauge: (from the Greek manos, sparse, and metron, measure). Apparatus for measuring the pressure of a fluid.

methane: First term CH4 of saturated hydrocarbons. (Methane is formed by the decomposition of certain organic materials. Natural gases, such as Lacq's, contain up to 98%; firedamp is an explosive mixture of methane and air. It is a gas. of weak odor, density 0,55, liquefying at - 164 ° C. It does not give an addition reaction. It is used in industrial heating and in the preparation of hydrogen.) Syn. Formene, marsh gas.

methyl: Univalent radical - CH3, which derives from methyl alcohol by removing the hydroxide.

methyl: (gr. methu, wine) Refers to certain derivatives of methane, among others alcohol (methyl alcohol or methanol).


oleate: Salt or ester of oleic acid.

oxacid: Acid in which the active hydrogen belongs to a hydroxyl group --OH.

oxide: (from gr. oxus, acid) Body resulting from the union of oxygen with a chemical element or a radical.

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Carbon monoxide: CO was discovered by Priestley. It is a colorless and odorless gas difficult to liquefy. It burns giving carbon dioxide or CO2.


peptide: Natural or synthetic compound, formed by the union of a limited number of amino acids, the bond being effected by loss of water between the amino group of a molecule and the carboxyl group of the neighboring molecule (peptide bond).

peptone: Polypeptide resulting from the partial hydrolysis of a protein by an enzyme.

polypeptide: Biochemistry. Protide formed from several amino acids, the carboxyl group of one being attached to the amino group of the other.

potassium: Potassium is the chemical element 19, with atomic mass K = 39,1 (kalium). It is a soft solid whose breakage is brilliant, but which immediately tarnishes in air by oxidation.

propionic: (gr. prôtos, prime, and piôn, fatty) Refers to the acid CH3CH2CO2H, higher homolog of acetic acid, and of compounds which are attached to it.

proteid: structure of proteins generic name of more complex than the polypeptides.

protide: Nitrogenous organic substances constituting living beings, and formed, at least in part, by a condensation of amino acids of general formula R_CHNH2_CO_OH. (The group of proteins includes peptides and proteins.)


Radical : A group of atoms whose existence is considered within a chemical molecule because it manifests a certain individuality in the reactions.


salification Production of a salt.

saponification: Transformation of fat into soap. By extension. Hydrolysis of esters, amides, nitriles, etc. (The actual saponification is the cutting of the esters by a sufficient quantity of alkali to salify all the acid thus liberated at the same time as the alcohol; it is a rapid and complete reaction.). Saponification index, index expressing in milligrams of potash (KPH) absorbed by 1 g of a fatty substance, the content of this body in saponifiable compounds. (This index is one of the essential characteristics of natural or synthetic fats.)

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fission: Multiplication of a living being by direct fragmentation not followed by growth. Fissiparity is opposed to the budding or separation of small fragments called to grow and differentiate. In scissiparous beings, each detached fragment is as large and as differentiated as the remaining stump.

Salt : Generic name of chemical compounds resulting from the action of an acid on a base.

silica: (lat. flint, silisis). Silicon oxide SiO2, found in a large number of minerals.

silicon: A carbon-like metalloid, entering into a large number of minerals (silica, silicates), and thereby forming 28% of the earth's crust.

sodium: Alkali metal very widespread in nature, especially in the state of chloride. Discovered in 1807 by Davy, sodium is chemical element no.11, with an atomic mass Na = 23,0. It is a soft white solid, which oxidizes quickly in air and which is stored in petroleum jelly. It is very oxidizable and reducing, and breaks down water when cold.

soda: Sodium hydroxide NaOH. Caustic soda NaOH is a white solid, melting at 320 ° C, very soluble in water. It is a strong base with many uses.

stearic: Said of an acid CH3 (CH2) 16CO2H, contained in fatty substances in the form of glyceride (stearin)

sulfate: Salt or ether of sulfuric acid H2SO4.


Buffer : Buffer system (Biochemistry), Name given to a solution whose concentration of hydrogen ions (pH) is not noticeably modified by the introduction of a strong base or acid.

labile: Refers to a substance that is destroyed at a higher or lower temperature (such as vitamin D at 120 ° C for example).


Univalent or monovalent: Which has a chemical valency equal to one.


Valencia: Ability to combine a chemical element with one or more hydrogen atoms.

Biochemistry definitions from A to G

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