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
organic compounds with the general formula (CH2O)n, including sugars, starches, and celluloses, that are an important source of food and energy for animals.
Catabolism
the 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.
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�C for water).
Cohesion
the force by which individual molecules stick together.
Freezing point
the temperature at which a liquid solidifies (0�C 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�C).
Hydrogen bond
a weak bond caused by electrostatic attraction between a positively-charged part of one molecule and a negatively-charged part of another.
Hydrophilic
molecules capable of interacting with water through hydrogen bonding (having an affinity for water).
Hydrophobic
molecules that lack an affinity for water (water insoluble).
Methane
a light, colourless gas (CH4).
Polarity
property of having distinct and opposite charges (poles).
Solubility
the property of a substance of being soluble (dissolved).
Solvent
a liquid in which substances (or solutes) are dissolved to form a solution.
Surface tension (of water)
the intermolecular hydrogen bonds between molecules of water at the surface.
Transparency
property that allows light to penetrate molecules of water.
Amylopectin
a soluble polysaccharide and highly-branched polymer of glucose found in plants as one of the two components of starch (the other being amylose).
Amylose
a polysaccharide found in plants as one of the two components of starch (making up approximately 20-30% of the structure).
Body mass index (BMI)
a measure for human body shape based on an individual's mass and height (kg/m2).
Cellulose
a polysaccharide with the formula (C6H10O5)n, consisting of a linear chain of between several hundred to over ten thousand ?-linked D-glucose units.
Condensation
formation of larger molecules involving the removal of water from smaller component molecules.
Disaccharide
a sugar (carbohydrate) composed of two monosaccharides joined by condensation.
Fatty acids
any of the group of a long chain of hydrocarbon derived from the breakdown of fats having a single carboxylic group and aliphatic tail.
Glycerol
a metabolic intermediate and structural component of the major classes of biological lipids, triglycerides, and phospholipids.
Glycogen
a branched polymer of glucose that is mainly produced in liver and muscle cells, and functions as secondary long-term energy storage in animal cells.
Isomers
chemical compounds of the same chemical formula but different structure (cis or trans).
Lactose
a disaccharide sugar that is commonly found in milk and consists of galactose and glucose.
Lipids
organic compounds, including the fats, oils, waxes, sterols, and triglycerides, that are insoluble in water,but soluble in non-polar organic solvents.
Maltose
a disaccharide formed when two glucose monomers join together.
Monomers
consist of a single component.
Monosaccharide
the simplest form of carbohydrate (for example fructose, glucose, and ribose) that constitutes the building blocks of a more complex form of sugars.
Monounsaturated
an unsaturated molecule that contains only one double or triple bond in the carbon chain.
Polymer
a compound made up of several repeating units (monomers).
Polysaccharide
a complex carbohydrate composed of a chain of monosaccharides joined together by glycosidic bonds.
Polyunsaturated
a type of molecule that contains more than one double or triple bond in the carbon chain.
Saturated fatty acids
a form of fatty acid that lacks unsaturated linkages between carbon atoms.
Starch
a polysaccharide carbohydrate (C6H10O5)n found in plants that consists of a large number of glucose monosaccharides.
Sucrose
a disaccharide composed of the monosaccharides glucose and fructose.
Triglycerides
an energy-rich compound made up of a single molecule of glycerol and three molecules of fatty acid.
Unsaturated fatty acid
a form of fatty acid that contains more than one double bond between carbon atoms.
Albumin
the main protein of human plasma. Its main function is to regulate the osmotic pressure of blood.
Amino acids
building block of proteins consisting of the basic amino group (NH2), the acidic carboxylic group (COOH), a hydrogen atom (-H), and an organic side group (R) attached to the carbon atom.
Amino group
NH2
Carboxylic group
COOH
Collagen
a glycoprotein that forms strong fibres, found in connective tissue and bone (the most abundant protein in the animal kingdom).
Condensation
formation of larger molecules from smaller component molecules involving the removal of water.
Denaturation
a structural change in a protein that results in a permanent loss of biological properties.
Dipeptide
two amino acids linked together.
Gene
a heritable section of DNA that controls a specific trait.
Immunoglobulins
group of large glycoproteins that function as antibodies in the immune response by binding with specific antigens.
Insulin
a hormone that lowers blood glucose levels by synthesizing glycogen.
Peptide bond
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.
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.
Proteome
the complete set of proteins that can be expressed by the genetic material of an organism.
Rhodopsin
a visual pigment consisting of retinal and opsin.
Ribosome
cell organelle functioning as the site of protein synthesis.
Rubisco (ribulose carboxylase)
is the enzyme that catalyses the first step of photosynthesis (probably the most abundant protein on Earth).
Active site
the specific portion of an enzyme that attaches to the substrate.
Catalase
an enzyme found in the blood, and in most living cells, that catalyses the decomposition of hydrogen peroxide into water and oxygen.
Denaturation
a structural change in a protein that alters its three-dimensional shape and causes the loss of its biological properties.
Enzyme activity
a measure of the ability of an enzyme to catalyse a specific reaction.
Enzymes
a class of proteins that catalyses chemical reactions.
Hydrolysis
decomposition of a chemical compound by reaction with water.
Lactase
the enzyme responsible for catalysing the split of lactose into galactose and glucose.
Lactose
a disaccharide (C12H22O11) found in milk that may be hydrolysed to yield glucose and galactose.
Metabolism
all of an organism's chemical processes.
Substrate
the substance on which an enzyme works.