CHEMISTRY GLOSSARY

methyl orange    →   metil oranž

Methyl orange is an acid-base indicator, in acid it turns red and in a base it turns yellow.

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

acid-base indicator    →   kiselo-bazni indikator

Acid-base indicator is a weak acid or weak base, such as litmus, methyl orange or phenolphthalein, which changes colour when it gains or loses an H⁺ ion.

adrenaline    →   adrenalin

Adrenaline was the first naturally produced hormone to be isolated in its pure state. It is known as epinephrine, but its chemical name is 1-[3,4-dihydroxyphenol]-2-methylaminoethanol. Adrenaline is a hormone, produced by the medulla of the adrenal glands, that increases heart activity, improves the power and prolongs the action of muscles, and increases the rate and depth of breathing to prepare the body for "fright, flight, or fight". At the same time it inhibits digestion and excretion.

cetane number    →   cetanski broj

Cetane number is a measure of the ignition quality of diesel fuel. It denotes the volume fraction of cetane (C₁₆H₃₄) in a combustible mixture (containing cetane and 1-methylnapthalene) whose ignition characteristics match those of the diesel fuel being tested. Cetane is a collection of un-branched open chain alkane molecule that ignites very easily under compression, so it was assigned a cetane number of 100, while alpha-methyl naphthalene was assigned a cetane number of 0.

coal tar    →   ugljeni katran

Coal tar is a material obtained from the destructive distillation of coal in the production of coal gas. The crude tar contains a large number of organic compounds (e.g. benzene, naphthalene, methylbenzene, etc.), which can be separated by fractional distillation.

homologous series    →   homologni niz

Series of compounds which have a common general formula and in which each member differs from the next member by a constant unit, which is the methylene group (-CH₂-) is called the homologous series. Members of a homologous series are called homolog.

An example of the homologous series with some of their homologs are given below. Straight chain alkanes having general formula C_nH_2n+2

indicator    →   indikator

Indicator is a substance used to show the presence of a chemical substance or ion by its colour. Acid-base indicators are compounds, such as phenolphtaleine and methyl orange, which change colour reversibly, depending on whether the solution is acidic or basic. Oxidation-reduction indicators are substances that show a reversible colour change between oxidised and reduced forms.

isoleucine    →   izoleucin

Isoleucine is hydrophobic amino acids with aliphatic side chain. It is one of the three amino acids having branched hydrocarbon side chains. The side chains of these amino acids are not reactive but, these residues are critically important for ligand binding to proteins, and play central roles in protein stability. Isoleucine is an essential amino acid, which means that humans cannot synthesize it, so it must be ingested.

• Abbreviations: Ile, I
• IUPAC name: 2-amino-3-methylpentanoic acid
• Molecular formula: C₆H₁₃NO₂
• Molecular weight: 131.12 g/mol

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