Microbiology terms - M
- macromolecule
- A large molecule formed from the connection of a number of small
molecules.
- macrophage
- Large noncirculating phagocytic cells involved in both phagocytosis and the
antibody production.
- magnetosome
- Small particle of Fe3O4 present in cells that exhibit magnetotaxis.
- magnetotaxis
- Movement toward the magnetic poles due to the presence of
magnetosomes.
- magnetotactic bacteria
- Bacteria that can orient themselves in the earth's magnetic field due to the
presence of magnetosomes.
- major histocompatability complex (MHC)
- A cluster of genes coding for cell surface proteins important in antigen
presentation to T cells.
- malignant
- In reference to a tumor, an infiltrating metastasizing growth no longer under
normal growth control.
- mast cell
- A type of connective tissue cell adjoining blood vessels throughout the body.
It secretes histamine, heparin, and other biologically active products and
participates in immediate type hypersensitivity reactions and in the
inflammatory response.
- medium (plural media)
- Any liquid or solid materials which is prepared for the growth, maintenance,
or storage of microorganisms. There are different types of media according
to the purposes: basal medium, defined medium, complex medium,
differential medium, selective medium, enriched medium, enrichment
medium, etc.
- meiosis
- In eukaryotes, reduction division, the process by which the change from
diploid to haploid occurs.
- memory cell
- A differentiated B lymphocyte capable of rapid conversion to an
antibody-producing plasma cell upon subsequent stimulation with antigen.
- mesophile
- Organism living in the temperature range around that of warm-blooded
animals, usually between 20-45°C.
- messenger RNA (mRNA)
- An RNA molecule transcribed from DNA which contains the information to
direct the synthesis of a particular protein.
- metabolism
- All biochemical reactions in a cell, both anabolic and catabolic.
- methanogen
- A methane-producing prokaryote; member of the Archaea.
- methanogenesis
- The biological production of methane.
- methanotroph
- An organism capable of oxidizing methane.
- methylotroph
- An organism capable of oxidizing organic compounds which do not contain
carbon-carbon bonds; if able to oxidize methane, also a methanotroph.
- MHC class I protein
- The antigen-presenting molecule found on all nucleated vertebrate cells.
- MHC class II protein
- The antigen-presenting molecule found primarily on macrophages and B
lymphocytes.
- microaerophilic
- Requiring oxygen but at a level lower than atmospheric.
- microbiology
- The study of microbioorganisms.
- microenvironment
- The immediate physical and chemical surroundings of a microorganism.
- micrometer
- One-millionth of a meter, or ten to the minus sixth meter (abbreviated um),
the unit used for measuring microorganisms.
- microorganism
- A living organism too small to be seen with the naked eye; includes bacteria,
fungi, protozoans, and microscopic algae; also includes viruses.
- microplasmodesmata
- Fine pores occuring in the septa of certain filamentous prokaryotes, such as
actinomycetes and cyanobacterial trichomes. These pores are used for
communication (exchange of metabolites) between two adjacent cells which
are separated by septa.
- microtubules
- Tubes that are the structural entity for eukaryotic flagella, have a role in
maintaining cell shape, and function as mitotic spindle fibers.
- minus (negative)-strand nucleic acid
- An RNA or DNA strand which has the opposite sense of (would be
complementary to) the mRNA of a virus.
- mitochondrion (plural mitochondria)
- Eukaryotic organelle responsible for processes of respiration and
electron-transport phosphorylation.
- mitogen
- A substance which is able to induce mitosis of certain eukaryotic cells.
- mitosis
- A highly ordered process by which the nucleus divides in eukaryotes.
- mixotroph
- An organism able to assimilate organic compounds as carbon sources while
using inorganic compounds as electron donors. Compare with autotroph and
heterotroph.
- mold
- A filamentous fungus.
- molecule
- The result of two or more atoms combining by chemical bonding.
- monoclonal antibody
- An antibody produced from a single clone of cells. This antibody has
uniform structure and specificity.
- monocyte
- Circulating white blood cell which contains many lysosomes and can
differentiate into a macrophage.
- monomer
- A building block of a polymer.
- monotrichous
- Having a single polar flagellum.
- morbidity
- Incidence of disease in a population, including both fatal and nonfatal cases.
- mortality
- Incidence of disease in population.
- motility
- The property of movement of a cell under its own power.
- mucilage
- A gumlike material covering some bacteria (e.g. cyanobacteria) to prevent
the water loss during the dryness.
- murein
- See peptidoglycan.
- mushroom
- A filamentous fungus that produces large, sometimes edible structure, called
fruiting body.
- mutagen
- A substance which causes the mutation of genes. Compare with carcinogen.
- mutant
- Refer to an organism, population, gene, or chromosome, etc which differs
from the corresponding wild type by one or more mutations.
- mutation
- An inheritable change in the base sequence of the DNA of an organism.
- mycelium
- A group or mass of hyphae.
- mycoplasma
- A group of bacteria without cell wall. They are grouped together with
gram-positive bacteria not because they are stained positive but because
they are phylogenetically close to the clostridia. The other important feature
of mycoplasma is that they are very small, probably the smallest organisms
capable of autonomous growth.
- mycorrhiza
- A symbiotic association between a fungus and the roots of a plant.
- mycosis
- An infection caused by fungi.
- myeloma
- A malignant tumor of a 4plasma cell (antibody-producing cell).
Compiled by Tsute Chen, Converted by Ben Hoyt