Microbiology terms - O
- obligate
- An adjective referring to an environmental factor (for example, oxygen)
which is always required for growth. For example, obligate aerobe.
Compare with facultative.
- obligate aerobe
- An organism which can grow only in the presence of oxygen (O2).
- oligonucleotide
- A short nucleic acid molecule, either obtained from an organism or
synthesized chemically.
- oligotrophic
- Describing a body of water in which nutrients are in low supply.
- oncogene
- A gene whose expression causes formation of a tumor.
- open reading frame (ORF)
- The entire length of a DNA molecule that starts with a start codon and ends
with a stop codon.
- operator
- A specific region of the DNA at the initial end of a gene, where the
repressor protein binds and blocks mRNA synthesis.
- operon
- A cluster of genes whose expression is controlled by a single operator.
Typical of prokaryotic cells.
- opsonization
- Promotion of phagocytosis by a specific antibody in combination with
complement.
- organelle
- A membrane-enclosed body specialized for carrying out certain functions;
found only in eukaryotic cells.
- organotroph
- In reference to energy source (electron donor) - An organism which obtains
energy by the metabolism of organic substrates (as electron donors). There
are two type of organotrophs: chemoorganotroph and photoorganotroph.
Compare with autotroph, lithotroph, heterotroph, phototroph.
- osmosis
- Diffusion of water through a membrane from a region of low solute
concentration to one of higher concentration.
- outbreak
- The occurrence of a large number of cases of a disease in a short period of
time.
- oxic
- Containing oxygen; aerobic. Usually used in reference to a microbial habitat.
- oxidation
- A process by which a compound gives up electrons, acting as an electron
donor, and becomes oxidized.
- oxidation-reduction (redox) reaction
- A coupled pair of reactions, in which one compound becomes oxidized,
while another becomes reduced and takes up the electrons released in the
oxidation reaction.
- oxidative phosphorylation
- The non-phototrophic production of ATP at the expense of a proton motive
force (PMF) formed by electron transport. Also electron-transport
phosphyrylation.
- oxygenic photosynthesis
- Use of light energy to synthesize ATP and NADPH by noncyclic
photophosphorylation with the production of oxygen from water.
Compiled by Tsute Chen, Converted by Ben Hoyt