## Even molecules and microorganisms show signs of behaviour

At the level of molecular biology, we can think about behaviour in terms of cooperation. This happens, for example, between genes that make up complex genomes. For the functionality of metabolic pathways, the cooperation of several enzymes, which are coded by individual genes, is necessary. Another example of coordinated behaviour at the molecular level is protein subunits that must work together to form a functional enzyme. However, in these cases it is still difficult to talk about "behaviour" as we know it in ordinary life. We also observe cooperation between individual cells. One example are microorganisms that show signs of social behaviour by sharing molecules secreted into the environment, including enzymes that break down food. At the same time, they can communicate with the help of various signalling molecules, which alert community members to the presence of danger in their surroundings. As communities in which microorganisms occur, we can consider cell colonies or more complex biofilms, which are formed by various types of microorganisms, including yeast or bacteria. With their metabolism, they can mutually compensate the needs of the various "inhabitants" of the biofilm, and this cooperation also helps in the defence against antimicrobial substances. Similar communication takes place between the cells that make up multicellular organisms, and their cooperation at every level is essential for the functioning of a complex organism.