An enzyme present in the latex of papaya and pineapple. As a protease, it has the ability to fragment proteins.

Human papillomaviruses (HPV) are the viruses responsible for contagious lesions on the skin and mucus membranes (warts, for instance). Some lead to the appearance of cervical cancer in women.

The word papyrus designates, firstly, a plant (Cyperus papyrus) once common on the banks of the Nile. In ancient times its stalks (similar to those of the elderberry) were cut into strips which were glued together to make leaves on which one could write. Hence, the second meaning of papyrus: the material that can be written on and the manuscript produced in this way. Papyrus made in Egypt was exported throughout the Mediterranean. Papyrology is the science of papyri.

Substances which, when placed within a magnetic field, become very weakly magnetic in the same sense or direction as the field.

Tissue assuring the essential functions of an organ (as opposed to the stroma).

Italian sociologist known for his research on the concept of efficiency. In his “Treatise of General Sociology” (1916), he places logical action which is linked to the economy alongside non-logical action which is linked to sociology. He also prioritised the importance of elites and the concept of the “circulation of elites”.

American sociologist who elaborated the theory of the systemic functionalism of action. Among those who influenced his research were Freud and Durkheim.

The pascal is a unit of pressure. One pascal is equivalent to the uniform pressure which, when applied to a flat surface area of one square metre, exerts a total force of one Newton perpendicularly to it. The bar is another commonly used unit of pressure: one bar equals 100,000 pascal.

The capability of an organism (virus, bacteria) or a substance to cause a disease.

Belgian politician. Elected as a member of parliament for the socialist party from 1932, he became a Minister in 1935 and Prime Minister in 1938. He was Foreign Minister in the Belgian government in exile in London during the war. After this, he followed a brilliant Ministerial career and was widely known on the international scene. Among other things, he was considered as one of the founding fathers of Europe. He was to be present of the General Assembly of the United Nations, President of the Parliamentary Assembly of ECSC (European Coal and Steel Community) and General Secretary of NATO.

Polymerase Chain Reaction is an in vitro molecular gene amplification technique which allows significant quantities of DNA or RNA sequences to be produced from a small quantity of nucleic acids.

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PBPs play an important role in the formation of peptidoglycan, a key component in the bacterial wall. These proteins are the targets of beta-lactamine type antibiotics, such as penicillin.

A molecule consisting of at least two amino acids linked by a peptide bond, or a CO-NH bond, a result of condensation between the amino group (-NH2) of the first amino acid and the carboxyl group (-CO2H) of the second amino acid.

A peptide sequence is the chain of amino acids that make up a given peptide. The sequence is generally read from the N-terminal end to the C-terminal end. It can be expressed by using the name of the amino acid (example: Glycine-Asparagine-Valine), a 3-letter abbreviation (Gly-Asn-Val), or more commonly, a 1-letter abbreviation (G-N-V).

The peripheral nervous system is made up of the complex of nerves attached to the central nervous system. There are two kinds of peripheral nerves, cranial nerves and rachidian nerves. We distinguish two peripheral nervous systems: the somatic nervous system (motor and sensation) and the vegetative (autonomous).

A cubic structure whose form is seen in many ABO3 oxides, in which the A atom is at the corners of the cube, the B atom in the middle, and the oxygen atoms in the centre of the face edges. Identified for the first time in the form of CaTiO3, this structure is named after the Russian mineralogist L. A. Perovski (1792-1856).

Petrochemistry is the science which focuses on the fabrication of synthetic materials (such as plastics) from the chemical derivatives of petrol.

Abbreviation of bacteriophage. Any virus that infects bacteria and can destroy them. Bacteriophages have a high level of specificity not only in a certain group of bacteria, but also in a species or even a bacterial strain.

The pharyngeal teeth of the clownfish are located within the branchial arches. In some species they are used to chew food, whilst in others they can be compared to a treadmill which carries food into the oesophagus. Fish also possess buccal teeth whose principal role is to grip food.

Chemical substances (or a mixture of substances) secreted by a body which influence the physiology or the behaviour of individuals of the same species.

A salt formed by phosphoric acid combining with a base. Phosphates are produced by the replacement of all or part of the hydrogen in phosphoric acid with metals.

Addition of a phosphate group (PO4) to a protein in one of the three potential phosphorylation sites or amino acids: serine, tyrosine or threonine. The phosphorylation of a protein often profoundly changes its activity as an enzyme or a receptor.

An apparatus that allows fine control of various parameters that influence the growth of photosynthetic microorganisms, and of the photoproduction of hydrogen.

A quantum of electromagnetic energy carrying light.

Time during a day from dawn to dusk; the number of hours of daylight.

A great orange peel, the photosphere is a thin surface layer which covers the stars. The Sun's photosphere has a thickness of 200km, whilst its rays are of the order of 700.000km. Its average temperature is in the neighbourhood of 6000°C.

Process that allows plants to synthesise their organic matter from light energy (solar or artificial).

A technology which uses plants to clean up soils.

A material is piezoelectric when it can be distorted when in an electric field. Conversely, the distortion of a piezoelectric crystal generates a difference in electric potential at its terminals. The piezoelectric effect is at the root of many applications, such as sonar and ultrasound.

The simple fact of receiving a treatment may have an influence on symptoms, regardless of the biological effects of the administered substance. This is called a placebo effect. In clinical experiments, it is essential to determine the effects linked to the treatment and those that are linked to the placebo effect. Therefore, it is common practice to compare the effects of the substance to be tested with those of a preparation with no biological effect but which looks exactly the same at first glance. This is a placebo. Neither the person taking part in the experiment nor the experimenter know whether the product administered corresponds to the drug or vaccine to tested or the placebo. This is called a double-blind test.

All the tissues and blood vessels from which an embryo takes all the nutrients it needs. It contains both the mother’s blood and the foetus’ blood. But the two never come into contact with each other, separated by the hemato-placental barrier. The placenta plays the following roles: - to feed and oxygenate the foetus; - to eliminate the toxins (urine, carbon dioxide, etc.) produced by the foetus since the organs that perform these roles (kidneys, liver) are not yet able to do so; - to act as an immunological shield, i.e. to prevent the microbes from getting through. However, substances pass through this barrier such as certain types of medication, certain viruses (aids, rubella, etc.) and pollutants such as tobacco, alcohol and drugs.

Inactive plasmatic protein involved, once activated, in numerous biological processes, including the coagulation and activation of growth factors.

A polymer is a molecule with a very high molecular weight, composed of elements that have weak molecular weight.

A system that conceives of the superhuman world in plural form. However, the ancient Greeks did not define their religion in this way. What we call Greek polytheism is a set of cultural practices and representations of the divine world which went across the whole of Hellenic society, flying in the face of the usual distinction between religion and laity, sacred and profane, public and private. In this multi-god system, deities are not simply juxtaposed with each other; their respective abilities are intertwined. Polytheistic language links deities to each other in configurations which vary according to places and circumstances, for which reason a deity cannot be studied in isolation.

The plurality that characterizes the divine world of ancient Greece is also found in each deity. The multiple abilities of a god, and the innumerable faces through which he is feared by the Greeks, constitute a veritable, well-linked, cohesive network. This network is a deity’s polyvalence.

A polemical discourse pitting the honest, hard working and homogenous people against lazy, dishonest and minority elites. Populism proposes to do away with intermediaries and mediations between the people and the exercise of power and promises a society in which the popular will would coincide on a daily basis with its being effective carried out.

Positron is the antiparticle linked to the electron – same mass, same spin, with an equal but opposite charge (positive).

Numerous diseases, or any other medical event, recorded in a determined population and including new cases as well as the old ones.

Organs where specific cells called lymphocytes mature. Among these organs are: the thymus gland, bone marrow, lymph nodes, amygdales, Peyer’s patches (in the small intestine), the appendix and some parts of the skin and mucous membrane. (source : vulgaris-medical)

A prime number is an integer that can only be divided by 1 and itself.

The principle of precaution is a guarantee against potential risks that are not yet identifiable given the actual state of our knowledge. This principle affirms that in the absence of formal scientific certainty, the existence of a risk of serious or irreversible damage imposes a responsibility, that some means of warning should be provided prior to the beginning of such damage.

Inference is a logical operation by which one accepts a proposition in accordance with its link with other propositions already held to be true. Probabilistic inference thus combines a degree of probability to a proposition, action or event in conjunction with another proposition, action or event.

A rigid tube extended from the head of certain insects or crustaceans. The term can also designate a mouth-piece that can pierce skin, and that can be used for sucking blood by certain insects and parasites.

Prokaryotes are living organisms whose cells, unlike those of eukaryotes, do not have a nucleus.

A substance, or combination of substances, whose decomposition or chemical reactions generates the energy for rocket self-propulsion.

Prostaglandins are fatty acids produced by cells. They work as mediators to stimulate adjacent cells. The signals they send activate the cells, increasing or reducing cell reactions.

Enzyme that breaks the protein peptide bonds

A molecule consisting of chains of amino acids linked together. Proteins determine the greatest part of living organism’s cell structures and functions. In this respect they are considered to be the major tools of the living world.

Protein degradation.

Enzymes, also called proteases, which break the peptide binding of proteins.

A doctrine of Christian churches stemming from the Reformation. Despite the large diversity of Protestant churches (Lutherans, Calvinists, Anglicans, etc.) and their independence, they are united by a number of characteristics. It is thus that Protestants consider the Bible as the sole source of faith and try to eliminate from religion everything that is not prescribed by the scriptures and the church’s early fathers, those most close in time to the apostolic era. It is for that reason that they translated and disseminated the holy texts in vernacular languages and encouraged education for the people. It is also generally agrees that, in Calvinist areas above all, the importance placed on personal judgement encouraged the appearance of democratic forms of government and that the abolition of the authority of the clergy opened up the path to modern capitalism.

A eukaryotic unicellular organism that may be similar to plants (such as diatoms), but may also be similar to animals (such as amoebae).

A forged piece of anti-Semitism, a complete fabrication put together in Paris in 1900-1901 by the Tsar's secret police service, whose foreign section was led from the French capital by Pierre Ivanovitch Ratchkovski. This document presented itself as the minutes or an account of secret meetings of the leaders at the highest level of ‘global Judaism’; it was supposed to reveal their programme for world domination and, at the same time, to warn the Russian leaders – and more widely the worldwide population – against the bosses of these supposedly dangerous conspirators.

A French writer and author of Remembrance of Things Past, a novel written between 1908-1909 and 1922 and published between 1913 and 1927. More than the narration of a sequence of given events, this work is interested in the memory of the narrator: his recollections and the connections between them. In the framework of Recherche are mounted Swann’s Way (1913), Within a Budding Grove (1919) and Time Regained, a posthumous work which appeared in 1927.

These spherical outcroppings of the respiratory bronchioles are the primary sites of gas exchange with the blood. In the alveoli, the air releases part of its oxygen to transform the dark red venous blood into bright red arterial blood. This transformation is called haematosis. Carbon dioxide enters the alveoli and is evacuated through expiration.