h2o, carbohydrates, lipids

ABO system

a system of four basic blood types (A, AB, B and O), based on the presence or absence of specific inherited antigens.

Adhesion

the force by which individual molecules stick to surrounding materials and surfaces.

Adipose tissue

a tissue found beneath the skin layer, containing fat cells.

Amphipathic

a molecule that has two different affinities - a polar end that is attracted to water (hydrophilic) and a non-polar end that is repelled by it (hydrophobic).

Anabolism

the synthesis of complex molecules from simpler molecules including the formation of macromolecules from monomers by condensation reactions.

Buoyancy

the ability of any fluid to provide a vertical upwards force on an object placed in or on it.

Capillary action

the tendency of a liquid to move up against gravity when confined within a narrow tube (capillary). Also known as capillarity.

Capillary tubes

channels with a very small internal diameter.

Catabolism

the breakdown of complex molecules into simpler molecules including the hydrolysis of macromolecules into monomers.

Cholesterol

a lipid of animal plasma membranes; a precursor of the steroid hormones in humans, formed in the liver and transported in the blood as lipoprotein.

Cohesion

force by which individual molecules of the same type attract and associate ('stick together').

Condensation

formation of larger molecules involving the removal of water from smaller component molecules.

Condensation reaction

reaction that combines two molecules while removing a small molecule (usually water).

Covalent bond

a bond between atoms in which electrons are shared.

Cytoplasm

fluid that fills each cell and is enclosed by the plasma membrane.

Disaccharide

a sugar that is a condensation product of two monosaccharides (e.g. maltose).

Double bond

a chemical bond in which two pairs of electrons are shared between two atoms. This type of bond involves four bonding electrons between atoms, rather than the usual two bonding electrons involved in a single bond.

Functional group

the chemically active part of a member of a series of organic molecules.

Glycocalyx

long carbohydrate molecules attached to membrane proteins and membrane lipids.

Glycolipid

lipids with a glycocalyx attached.

Glycoprotein

membrane protein with a glycocalyx attached.

Glycosidic linkage

a covalent bond between monosaccharide residues in disaccharides and polysaccharides.

Goldilocks zone

also known as the 'habitable zone'; the area around a star where it is not too hot or too cold for liquid water to exist on the surface of surrounding planets.

Hexose

a 6-carbon monosaccharide sugar.

Hormones

chemical messengers that are produced and secreted from the cells of the ductless or endocrine glands.

Hydrogen bond

a weak bond caused by electrostatic attraction between a positively charged part of one molecule and a negatively charged part of another.

Hydrolysis reaction

reaction where hydrogen and hydroxide ions from water are added to a large molecule causing it to split into smaller molecules.

Hydrophilic

attracted to water; e.g. hydrogen bonds are readily formed between a molecule and water.

Hydrophobic

repelled by water.

Isomer

chemical compounds of the same chemical formula but different structural formulae.

Lysis

breakdown, typically of cells.

Macromolecule

very large organic molecule (e.g. protein, nucleic acid or polysaccharide).

Metabolism

integrated network of all the biochemical reactions of life.

Metabolite

a chemical substance involved in metabolism.

Monomer

a molecule that chemically combines with other monomers, via covalent bond formation, to form a polymer.

Monosaccharide

any of the class of sugars (e.g. glucose) that cannot be hydrolysed to give a simpler sugar.

Oestradiol

a steroid hormone; a sex hormone of female mammals.

Pentose

a 5-carbon monosaccharide sugar.

Phospholipid

formed from a triacylglycerol in which one of the fatty acid groups is replaced by an ionized phosphate group.

Polar molecule

a molecule where there is an unequal distribution of electrical charge: one end is slightly positive and the other end is slightly negative.

Polymer

large organic molecules made up of repeating subunits (monomers).

Polymerization

process by which relatively small molecules, called monomers, combine chemically to produce a larger molecule called a polymer.

Polysaccharide

very high molecular mass carbohydrates formed by condensation of large numbers of monosaccharide units, with the removal of water.

Progesterone

hormone released by the corpus luteum that stimulates the uterus to prepare for pregnancy.

Saturated fat

fat with a fully hydrogenated carbon backbone (i.e. no double bonds present).

Solvent

a liquid in which another substance can be dissolved.

Specific heat capacity

the amount of energy required to raise the temperature of 1kg of a substance by 1°C.

Steroid

a group of four-ring hydrocarbons, of which cholesterol, oestradiol and testosterone are examples.

Surface tension

property of the surface of a liquid that allows it to resist an external force, due to the cohesion between water molecules.

Testosterone

a steroid hormone; the main sex hormone of male mammals.

Thermal conductivity (k)

the measure of how easily heat flows through a specific type of material.

Triglyceride

an ester made from glycerol and three fatty acid groups.

Unsaturated fat

fat with double bond(s) between carbons in the hydrocarbon chain.

Viscosity

the resistance to flow by a medium