G

Gene: One of many discrete units of hereditary information located on the chromosomes and consisting of DNA.

Gene cloning: The formation of a bacterium, carrying foreign genes in a recombinant plasmid, of a clone of identical cells containing the replicated foreign genes.

Genome: The complete complement of organism genes, an organisms genetic material.

Genomic library: A set of thousands of DNA segments from a genome, each carried by a plasmid or phage.

Genotype: The genetic makeup of an organism.

Golgi apparatus: An organelle in eukaryotic cells containing cells consisting of stacks of membranes that modify, store, and route products of the endoplasmic reticulum.

H

Half-life: The time taken for the concentration of a xenobiotic in a body fluid to decrease by half.

Histamine: A mediator of inflammatory reactions in the body, which may be part of an allergic reaction. Present in preformed granules in mast cells and basophils.

Hyperpolarisation: An electrical states whereby the inside of the cell is made more negative relative to the outside than at the resting membrane potential. A neuron membrane is hyperpolarised if a stimulus increases its voltage from the resting potential of -70mV, reducing the chance that the neuron will transmit a nerve impulse.

I

Inhibitory postsynaptic potential (IPSP): An electrical charge (hyperpolarisation) in the membrane of a postsynaptic neuron caused by the binding of an inhibitory neurotransmitter from a presynaptic cell to a postsynaptic receptor; makes it more difficult for a postsynaptic neuron to generate an action potential.

Ion: An atom that has gained or lost electrons, thus acquiring a charge.

Ion-channel-linked receptors: This class of receptors is linked to ion channels, the conductance of which is modulated by the binding of agonist or antagonists.

Ischemia: The condition where there is reduced or blocked blood flow to a tissue, which will lead to ischemic tissue damage.