CHEMISTRY GLOSSARY

ligand field theory    →   teorija ligandnog polja

Ligand field theory is a description of the structure of crystals containing a transition metal ion surrounded by nonmetallic ions (ligands). It is based on the construction of molecular orbitals involving the d-orbitals of the central metal ion and combinations of atomic orbitals of the ligands.

leucine    →   leucin

Leucine is hydrophobic amino acids with aliphatic side chain. It has one additional methylene group in its side chain compared with valine. The nonpolar hydrophobic amino acids tend to cluster together within proteins, stabilizing protein structure by means of hydrophobic interactions. Leucine is an essential amino acid, which means that humans cannot synthesize it, so it must be ingested.

• Abbreviations: Leu, L
• IUPAC name: 2-amino-4-methylpentanoic acid
• Molecular formula: C₆H₁₃NO₂
• Molecular weight: 131.17 g/mol

liquid crystal    →   tekući kristal

Liquid crystals or crystalline liquids are a physical state between crystals and melts. The liquid crystalline phase - the so-called mesophase - is formed at the melting point. The most important (usable) mesophases are nematic, cholesteric and smectic phase, having different molecular orientations.

lysine    →   lizin

Lysine is an electrically charged amino acids with basic side chains. Lysine is a base, as are arginine and histidine. The amino group is highly reactive and often participates in reactions at the active centers of enzymes. Lysine plays an important role in coordinating negatively charged ligands. It is an essential amino acid, which means that humans cannot synthesize it, so it must be ingested.

• Abbreviations: Lys, K
• IUPAC name: 2,6-diaminohexanoic acid
• Molecular formula: C₆H₁₄N₂O₂
• Molecular weight: 146.19 g/mol

metabolism    →   metabolizam

Metabolism is a sum of all chemical and physiological processes by which the body builds and maintains itself. It is a process of building the body’s molecular structures from nutrients (anabolism) and breaking them down for energy (catabolism).

macromolecule    →   makromolekule

Macromolecule is a molecule of high relative molecular mass (molecular weight), the structure of which essentially comprises the multiple repetitions of units derived, actually or conceptually, from molecules of low relative molecular mass. The types of macromolecules are natural and synthetic polymers, carbohydrates, lipids, proteins etc. Cellulose is a polysaccharide that is made up of hundreds, even thousands of glucose molecules strung together.

methionine    →   metionin

Methionine is neutral amino acids with polar side chains. It is one of the two sulfur-containing amino acids. Methionine is a fairly hydrophobic amino acid and typically found buried within the interior of a protein. It can form stacking interactions with the aromatic moieties of tryptophan, phenylalanine, and tyrosine. It is an essential amino acid, which means that humans cannot synthesize it, so it must be ingested.

• Abbreviations: Met, M
• IUPAC name: 2-amino-4-methylsulfanylbutanoic acid
• Molecular formula: C₅H₁₁NO₂S
• Molecular weight: 149.21 g/mol

molar mass    →   molarna masa

Molar mass is the mass of one mole of a substance.

It is normally expressed in units of g mol^-1, in which case its numerical value is identical with the relative molecular mass.

Newtonian fluid    →   Newtonski fluid

Newtonian fluid is a fluid whose viscosity does not depend on gradients in flow speed. Gases and low-molecular weight liquids are usually Newtonian fluids.

oligomer    →   oligomer

Oligomer is a substance consisting of molecules of intermediate relative molecular mass (molecular weight), the structure of which essentially comprises the multiple repetitions of units derived, actually or conceptually, from molecules of low relative molecular mass. In contrast to a polymer, the properties of an oligomer can vary significantly with the removal of one or a few of its units.