Microbiology is the study of microorganisms, which are defined as any microscopic organism that comprises either a single cell (unicellular), cell clusters or no cell at all (acellular). This includes eukaryotes, such as fungi and protists, and prokaryotes. Viruses and prions, though not strictly classed as living organisms, are also studied.
- Microbiology is the study of microscopic organisms, those being unicellular (single cell), multicellular (cell colony), or acellular (lacking cells). As an application of microbiology, medical microbiology is often introduced with medical principles of immunology as microbiology and immunology. Otherwise, microbiology, virology, and immunology as basic sciences have greatly exceeded the medical variants, applied sciences.
- Pathogenicity and virulence are terms that refer to an organism's ability to cause disease. Pathogenicity is the ability of a microbe to cause disease and inflict damage upon its host, whereas virulence is the degree of pathogenicity within a group or species of microbes as indicated by case fatality rates and/or the ability of the organism to invade the tissues of the host. The pathogenicity of an organism, that is its ability to cause disease, is determined by its virulence factors.
- Eukaryote organisms have one or more cells with a nucleus and other organelles enclosed within membranes.
- Innate immunity is an antigen-nonspecific defence mechanisms that a host uses immediately or within several hours after exposure to almost any microbe. This is the immunity one is born with and is the initial response by the body to eliminate microbes and prevent infection. Innate immunity can be divided into immediate innate immunity and early induced innate immunity. In this section we will learn about immediate innate immunity.
- The adaptive immune system is a subsystem of the overall immune system that is composed of highly specialized, systemic cells and processes that eliminate or prevent pathogen growth. Adaptive immunity creates immunological memory after an initial response to a specific pathogen, and leads to an enhanced response to subsequent encounters with that pathogen. This process of acquired immunity is the basis of vaccination.
- The genome of prokaryotes is usually made ​​up of one ''chromosome'' and plasmids. Eukaryota however, contain a larger number of chromosomes - we distinguish two types of eukaryota's chromosomes (nuclear and mitochondrial) and sometimes even plasmids. Most of what we know about the chromosomes of prokaryotes have been obtained from studies of E.coli – it is the organism of choice for such research of prokaryotes. Chromosome consists of double–stranded circular DNA.