Glossary

Codon - a frame of three consecutive bases on DNA or RNA that corresponds to a particular amino acid in a polypeptide.

Deamination - the removal of an amine group from a molecule

Dopaminergic neurons - neurons which release dopamine

Enzyme - Enzymes are large molecules called macromolecules that speed up the rate of usually very specific reactions. They do this by latching onto the molecule they are going to work on, and change some small part of it. Another characteristic of these catalytic proteins is their ability to be reused time and time again. This means that only a small concentration of enzyme is needed to catalyze the reaction. They are made up of a long string of amino acids, which are small nitrogen (N) and carboxylic acid (COOH) containing compounds.

Exon - the part of a gene or mRNA that specifies the amino acid sequence for a protein.

Intron - the part of a gene or mRNA that is not used in the making of functional messenger RNA (The junk part of DNA). This sequence does not code for any amino acid.

Mutation - a change of the base sequence in DNA. a point mutation is one that substitutes one base for another. A silent mutation is one that does not change what is coded for even though the though a base has been changed.

Nucleotide - part of the DNA structure that consists of three distinct parts: a phosphate group bound to a sugar, which is in turn bound to a nitrogeous base. The bases vary to form different nucleotides and these nucleotides are bound together sugar to phosphate in order to form a single strand of DNA.

Recessive gene - a gene that is inferior to another gene that controls the same trait (the dominant gene). The inferior gene does not get expressed in the presence of a dominant gene.

Restriction endonucleases - important enzymes that have the ability to cleave DNA at particular base pair sequences called restriction sites. Each endonuclease recognizes a specific sequence of base pairs.

Restriction Fragment Length Polymorphisms (RFLPs) - fragments of DNA that result from the presence of cleavage sites (restriction sites) for enzymes that cut DNA into pieces. They are always the same for the same genes in humans.

Restriction site - a sequence of base pairs that is recognised by a specific enzyme (restriction endonucleases) that cleaves (cuts) DNA into segments. The cleavage occurs at this point. There are several different restriction sites.

Serotonergic Neurons - neurons which secrete the neurotransmitter serotonin

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