The 3D structure of a protein depends on its amino acid sequence.
Energy-storing molecule of cells. In eukaryotes ATP is generally produced in the mitochondria.
Basic unit of a protein. Every protein is a succession of amino acids linked to one another. There are 20 different amino acids, each of which is symbolised by a letter: A (alanine), C (cysteine), D (asparagine), E (glutamine), F, G, H, I, K, L, M, N, P, Q, R, S, T, V, W, and Y.
An antibiotic is a natural substance produced by bacteria or fungi for instance. Much like a chemical weapon, an antibiotic will act upon other species of bacteria or fungi by either killing them or slowing down their proliferation. Currently, many antibiotics are made in the laboratory and are therefore artificial.
An antibody is a protein that is produced by cells known as B lymphocytes, which are part of the immune system. Antibodies are found in different fluids (blood, saliva...). Their role is to detect the presence of foreign bodies, i.e. other proteins or bits of protein which belong to a virus for example. When this happens, a defence response, known as the immune reaction, is triggered off and the intruder is eliminated. Antibodies can also recognise cancer cells.
An antigen is generally a sugar, a protein, or bit of protein, which belongs to something foreign which has entered our body (pollen, virus, bacteria...). Antigens are like flags which warn our body that there is an intruder. They are recognised by antibodies, and are at the heart of the immune reaction.
Basic unit of matter (inert and living), consisting of a nucleus around which electrons rotate.
Bacteria are unicellular micro-organisms that have no nucleus and can live in a variety of environments (air, soil, water, other organisms...). In common usage, 'bacteria' includes bacteria and archaea (formerly known as archaebacteria) that generally live in extreme conditions (high acidity and elevated temperatures for instance).
Branch of biology that studies chemical reactions in living organisms, such as the production of energy in cells, or the synthesis and degradation of lipids.
Bioinformatics is a field in the life sciences which uses computer programs, mathematics and statistics to store, analyse and visualise biological data such as DNA sequences (genomes), protein sequences or experimental results.
Field of science where techniques, which make use of living organisms (bacteria, yeast...) or some of their genes or proteins, are applied to the food industry, agriculture, pharmaceuticals and medicine.
Abnormal proliferation of cells (tumour), caused by uncontrolled cell division.
The cell is the smallest unit necessary for the constitution of a living being. The number of cells in a given species varies: bacteria are made up of only one cell, the common earthworm, C.elegans, is made up of about 1’000 cells, while you need 100’000 billion cells to make a human being.
Protein lodged in a cell's membrane that acts like a pore through which only certain small molecules are permitted to pass.
A chromosome is a more or less compactly wound thread of DNA, a little like a ball of wool. In some organisms, including humans, chromosomes appear in their popular 'X' form at the time of cell division, and dark and light horizontal bands alternate along their length when specific colourings are used. The topography of these bands is characteristic of a chromosome and used to identify it.
DNA is a chain of nucleotides that are linked to one another via chemical bonds. There are four different nucleotides: adenine, cytosine, guanine and thymine symbolised by A, C, G and T respectively. The order of nucleotides is very precise in DNA, and is the basis of genetic information. More often than not, DNA has a 'double helix' structure made up of two long strands. The strands are linked to each other via the nucleotides, where adenine (A) always binds to thymine (T), and guanine (G) to cytosine (C), rather like a twisted ladder.
Computerised encyclopedia that organises data in a very structured way in order to store huge quantities of information as efficiently as possible (synonym: database).
Computerised encyclopedia that organises data in a very structured way in order to store huge quantities of information as efficiently as possible (synonym: databank).
Region of about 200 amino acids within a protein, which has a defined structure and a particular role. On average, one protein is made up of 2 to 3 different domains.
An enzyme is a protein which accelerates chemical reactions in an organism. As an example, proteases are enzymes that are able to sever other proteins, just like a pair of scissors.
Eukaryotes are organisms whose cells have a nucleus in which the chromosomes are confined. Animals (humans included), plants and fungi are eukaryotes. Prokaryotes, on the other hand, do not have a nucleus and their chromosomes are ‘free’.
Describes the transformations undergone by living organisms (animals, plants and bacteria) as time goes by. Evolution is the consequence of gradual genetic changes. It drives the creation of new species from a common ancestor. The evolution of species can be represented by a phylogenetic tree.