Driver fatigue – an accident waiting to happen
Glossary
amino acid. The basic building block of protein. All amino acids contain an amino (NH2) end, a carboxyl end (COOH) and a side group (R). In proteins, amino acids are joined together when the NH2 group of one forms a bond with the COOH group of the adjacent amino acid. The side group is what distinguishes each of the amino acids from the others.
There are 20 common amino acids: alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine.
autonomic nervous system. The part of our nervous system that regulates essential functions such as heartbeat and breathing, functions that occur without conscious involvement. It is sometimes called the involuntary nervous system. For more information see The autonomic nervous system (Neuroscience for Kids, University of Washington, USA) and Autonomic nervous system (National Dysautonomia Research Foundation, USA).
blood alcohol concentration (BAC). The concentration of ethanol in the blood, which is a key measure in determining the effect of ethanol on the body. It is measured in grams of ethanol per 100 millilitres of blood. For example, people with a BAC of 0.05 grams per 100 millilitres – the legal limit for most drivers – have 0.05 grams of alcohol in their body for every 100 millilitres of their blood.
DNA (deoxyribonucleic acid). The nucleic acid forming the genetic material of all organisms with the exception of some viruses which have RNA. DNA is present in the nucleus and other organelles such as mitochondria and chloroplasts.
gene. The basic unit of inheritance. A gene is a segment of DNA that specifies the structure of a protein or an RNA molecule.
hormone. A substance produced in one part of the body and carried by the blood to another part of the body where it causes a response (eg, insulin, produced by the pancreas, that promotes the uptake of glucose by body cells). For more information see The hormones of the human (Kimball's Biology Pages, USA) and The hormones (Center for Bioenvironmental Research, Tulane and Xavier Universities, USA).
hypothalamus. A part of the brain that is connected to, and controls activity in, the pituitary gland. It also controls various aspects of homeostasis such as regulation of body temperature and appetite. There are regions of the hypothalamus that are associated with aggressive behaviour.
melatonin. A hormone that can influence the hypothalamus and pituitary gland and may affect appetite and sleep. It is derived from the amino acid, tryptophan.
protein. A large molecule composed of a linear sequence of amino acids. This linear sequence is a protein's primary structure. Short sequences within the protein molecule can interact to form regular folds (eg, alpha helix and beta pleated sheet) called the secondary structure. Further folding from interaction between sites in the secondary structure forms the tertiary structure of the protein.
Proteins are essential to the structure and function of cells. They account for more than 50 per cent of the dry weight of most cells, and are involved in most cell processes. Examples of proteins include enzymes, collagen in tendons and ligaments and some hormones. More information can be found at Protein structure and diversity (Molecular Biology Notebook, Rothamsted Research, UK).
Page updated August 2006.