CHEMISTRY GLOSSARY

glutamic acid    →   glutaminska kiselina

Glutamic acid is an electrically charged amino acids. It is one of the two amino acids that contain a carboxylic acid group in its side chains. These acids play important roles as general acids in enzyme active centers, as well as in maintaining the solubility and ionic character of proteins. Glutamic acid is commonly referred to as glutamate, because its carboxylic acid side chain will be deprotonated and thus negatively charged in its anionic form at physiological pH. Glutamic acid is referred to as a non-essential amino acid because a healthy human can synthesize all the glutamic acid needed for normal body function from other amino acids.

• Abbreviations: Glu, E
• IUPAC name: 2-aminopentanedioic acid
• Molecular formula: C₅H₉NO₄
• Molecular weight: 147.13 g/mol

lactic acid    →   mliječna kiselina

Lactic acid is an acid produced as a result of anaerobic respiration in muscles and red blood cells, i.e. when glycogen is used as an energy source for respiration rather than oxygen. After production, it is converted back to glycogen in the liver. The build up of large amounts of lactic acid in the blood can lead to stress and toxic effects. High levels are usually a result of sustained, excessive exercise.

lead-acid battery    →   olovni akumulator

Lead-acid battery is a electrical storage device that uses a reversible chemical reaction to store energy. It was invented in 1859 by French physicist Gaston Planté. Lead-acid batteries are composed of a lead(IV) oxide cathode, a sponge metallic lead anode and a sulphuric acid solution electrolyte.

In charging, the electrical energy supplied to the battery is changed to chemical energy and stored. The chemical reaction during recharge is normally written:

In discharging, the chemical energy stored in the battery is changed to electrical energy. During discharge, lead sulfate (PbSO4) is formed on both the positive and negative plates. The chemical reaction during discharge is normally written:

Lead acid batteries are low cost, robust, tolerant to abuse, tried and tested. For higher power applications with intermittent loads however, they are generally too big and heavy and they suffer from a shorter cycle life.

saturated fatty acid    →   zasićena masna kiselina

Saturated fatty acid is a fatty acid carrying the maximum possible number of hydrogen atoms (It doesn’t have any double bounds in the alkyl chain). The most important of these are:

unsaturated fatty acid    →   nezasićena masna kiselina

Unsaturated fatty acid is a fatty acid whose carbon chain can absorb additional hydrogen atoms. Their carbon chain has one or more double or triple valence bond per molecule. The most important of these are:

RNA    →   RNK

RNA is abbreviation for ribonucleic acid.

accumulator    →   akumulator

Accumulator (secondary cell, storage battery) is a type of voltaic cell or battery that can be recharged by passing current through it from an external D.C. supply. The charging current reverses the chemical reactions in the cell. The common types are the lead-acid accumulator and the nickel-cadmium cell.

acetal    →   acetal

Acetals are organic compounds having the structure R₂C(OR’)₂ (R’ ≠ H). They are organic compounds formed by addition of alcohol molecules to aldehyde or ketone molecules. Originally, the term was confined to derivatives of aldehydes (one R = H), but it now applies equally to derivatives of ketones (neither R = H ). Mixed acetals have different R’ groups. The formation of acetals is reversible; acetals can be hydrolysed back to aldehydes (ketone) in acidic solutions.

Acetal, 1,1-diethoxyethane (CH₃CH(OC₂H₅)₂), is an organic compound, pleasant smelling, formed by addition of ethyl alcohol to ethanal (acetaldehyde). It is used as a solvent and in synthetic organic chemistry.

acetate    →   acetat

1. Acetate is an ion formed by removing the acidic hydrogen from acetic acid, HC₂H₃O₂.

2. Acetate is a compound derived by replacing the acidic hydrogen in acetic acid.

3. Acetate is a fibre made of cellulose acetate.

adenine    →   adenin

Adenine is a purine derivative. It is one of the major component bases of nucleotides and the nucleic acid DNA and RNA.