2.1 Amino acid: building block of proteins that consists of a basic amino group (NH2), an acidic carboxylic group (COOH), a hydrogen atom (-H), and an organic side group (-R) attached to the carbon atom. Anabolism: the synthesis of complex molecules from simpler molecules, including the formation of macromolecules from monomers by condensation reactions. Carbohydrates: compounds with the general formula (CH2O)n, including sugars, starches, and celluloses, that are an important source of food and energy for animals. Catabolismthe breakdown of complex molecules into simpler molecules, including the hydrolysis of macromolecules into monomers. Covalent bonds: a chemical bond formed by the sharing of one or more electrons, especially pairs of electrons, between atoms. Disaccharide: sugar (carbohydrate) composed of two monosaccharides joined by condensation. Glucose: a simple monosaccharide sugar (C6H12O6) that serves as the main source of energy and as an important metabolic substrate for most living organisms. Lipids: organic compounds, including the fats, oils, waxes, sterols, and triglycerides, that are insoluble in water, but soluble in non-polar organic solvents. Metabolism: the process involving biochemical reactions of life. Monosaccharide: the simplest form of carbohydrate (examples include fructose, glucose, and ribose) that constitutes the building blocks of more complex forms of sugar. Nucleic acids: linear chains (DNA or RNA) of monomeric nucleotides, whereby each monomeric unit is composed of phosphoric acid, sugar, and nitrogenous base. Peptide bonds: a covalent bond that joins amino acids, at the carboxyl group of one amino acid to the amino group of the other amino acid, with the release of a molecule of water. Phospholipids: a lipid consisting of a glycerol bound to two fatty acids and a phosphate group. Polypeptides: a polymer of amino acids joined together by peptide bonds. Protein: organic molecule composed of polymers of amino acids joined together by peptide bonds and taking a particular three-dimensional shape. Ribose: a monosaccharide (chemical formula C5H10O5) found in RNA and other metabolically important compounds. Saturated fat: a fatty acid with all potential hydrogen binding sites filled. Saturated fatty acid: a form of fatty acid that lacks unsaturated linkages between carbon atoms. Steroids: lipid-based hormones that are related to the four-ring structure of cholesterol. Triglycerides: an energy-rich compound made up of a single molecule of glycerol and three molecules of fatty acid. Urea: a molecule created from ammonia and carbon dioxide as the final nitrogenous excretion product of many organisms.
2.2 Adhesion: the force by which individual molecules cling to surrounding material and surfaces. Boiling point: the temperature at which the vapour pressure of a given liquid reaches atmospheric pressure and thus starts to boil (100? for water). Cohesion: the force by which individual molecules stick together. Freezing point: the temperature at which a liquid solidifies (0? for water). Specific heat capacity: the amount of energy required to raise the temperature of water by one degree Celsius (water has to absorb 4.184 joules of heat for the temperature of one gram of water to increase by 1?). Hydrogen bond: a weak bond caused by electrostatic attraction between a