Microbiology terms - C
- Calvin cycle
- The biochemical route of carbon dioxide fixation in many autotrophic organisms.
- cancer
- A malignant, invasive cellular tumor that has the capability of spreading throughout the body
or body parts.
- capsid
- The protein coat of a virus.
- capsomere
- An individual protein subunit of the virus capsid.
- capsule
- A compact layer of polysaccharide exterior to the cell wall in some bacteria. See also
glycocalyx and slime layer.
- carbohydrate
- Any chemical compound which consists of only carbon (C), oxygen (O), and hydrogen (H)
elements, for examples, sugars, starches, and cellulose are carbohydrates. Also the ratio of
hydrogen to oxygen atoms in carbohydrates is usually 2:1.
- carboxyl group
- -COOH
- carboxysomes
- Polyhedral cellular inclusions of crystline ribulose bisphosphate carboxylase (RubisCO), the
key enzyme of the Calvin cycle.
- carcinogen
- A substance which causes the initiation of tumor formation. Frequently mutagen.
- catabolism
- The biochemical processes involved in the breakdown of organic compounds, usually leading
to the production of energy.
- catabolite repression
- Repression of a variety of unrelated enzymes when cells are grown in a medium containing
glucose.
- catalysis
- Increase in rate of a chemical reaction.
- catalyst
- A substance that promotes a chemical reaction by lowering the activation energy without
itself being changed in the end. Enzyme is a type of catalysts.
- CD4 cells
- T helper cells which are targets for HIV infection.
- cell
- The fundamental unit of living matter.
- cell-mediated immunity
- An immune response generated by the activities of non-antibody-producing cells such as T
cells. Compare with humoral immunity
- cell membrane
- See cytoplasmic membrane.
- cell wall
- The layer or structure that lies outside the cytoplasmic membrane; it supports and protects
the membrane and gives the cell shape.
- cellular microbiology
- A new discipline emerging at the interface between cell biology and microbiology. One major
focus of this new field is on the interference of pathogenic bacteria with many eukaryotic cell
functions, such as maturation of intracellular compartments, internal cellular communication,
or even cell division and differentiation. The study of cellular mcirobiology in this respect, is
providing a sophisticaled tool kit for mammalian cell biologists. (Ref: Science 271:315,
1996).
- cellulose
- A glucose polysaccharide (with beta-1,4-linkage) that is the main compnent of plant cell
walls.
- CFU
- Stands for colony-forming unit.
- chaperonin
- A protein that aids in the correct folding of other proteins and the assembly of multisubunit
structures.
- chaperone
- A protein that affect the folding of other proteins or the assembly of complex structures.
- chemiosmosis
- The use of ion gradients across membranes, especially proton gradients, to generate ATP.
See proton motive force.
- chemolithotroph
- An organism which obtains its energy from the oxidation of inorganic compounds.
- chemoorganotroph
- An organism which obtains its energy from the oxidation of organic compounds.
- chemostat
- A continuous culture device controlled by the concentration of limiting nutrient and dilution
rate.
- chemotaxis
- Movement toward or away from a chemical.
- chemotherapy
- Treatment of infectious disease with chemicals or antibiotics.
- chlorination
- A highly effective disinfectant procedure for drinking water using chlorine gas or other
chlorine-containing compounds as disinfectant.
- chlorophyll
- The green pigment required for photosynthesis. It consists of a light-sensitive tetrapyrrole ring
with a magnesium atom in the center.
- chloroplast
- The chlorophyll-containing organelle of photosynthetic eukaryotes.
- chlorosome
- A cigar-shaped structure bounded by a nonunit membrane and containing the light harvesting
bacteriochlorophyll in green sulfur bacteria and in Chloroflexus.
- cholesterol
- A type of sterols occurring widely in animal tissues as well as in some higher plants and algae.
Cholesterol is notorious yet important. It is infamous among the public because of its link
between the elevated serum cholesterol level and the cardiovascular disease; it is important
because cholesterol is the precursor for some very important steroids such as bile acids and
hormones.
- chromatography
- Any technique which is used to separates different species of molecules (or ions) by
subjecting them to two different carrier phases: mobile and stionary phases. These phases
can be solid, liquid, or gaseous, according to the type of chromatography. Due to the
different adsorption or affinity to either phase, molecules of different species may be
separated.
- chromogenic
- Producing color; a chromogenic colony is a pigmented colony.
- chromosome
- A genetic element carrying genes essential to cellular metabolism. Prokayrotes typically have
a single chromosome, consisting of a circular DNA molecule. Eukaryotic cells contain several
chromosomes, each contaiing a linear DNA molecule complexed with specific proteins.
- chronic
- Longer-term infection.
- cilium (plural cilia)
- Threadlike appendages that extend from the surface of some protozoa that beat rhythmically
to propel them ; cilia are membrane-bound cylinders with a complex internal array of
microtubules, usually in a 9+2 pattern. Compare with flagella.
- classification
- The arrangement of organisms into groups based on mutual similarity or evolutionary
relatednedd.
- clonal selection
- A theory that each B or T lymphocyte, when stimulated by antigen, divides to form a clone of
itself.
- clone
- 1. A population of cells all descended from a single cell.
2. A number of copies of a DNA fragment to be replicated by a phage or plasmid.
- cloning vector
- A DNA molecule that is able to bring about the replication of foreign DNA fragments.
- coccobacillus (plural: coccobacilli)
- A bacterium with a shape intermediate between coccus and bacillus.
- coccus (plural: cocci)
- A bacterium with a rounded or spherical shape.
- colony
- A clone of bacterial cells on a solid medium that is visible to the naked eye.
- coccoid
- Sphere-shaped.
- codon
- A sequence of three purine and/or pyrimidine bases in mRNA that encodes a specific amino
acid.
- coenzyme
- A low-molecular-weight chemical which participates in an enzymatic reaction by accepting
and donating electrons or functional groups. Examples: NDA+, FAD.
- coliform
- Gram-negative, nonsporing, facultative rods that ferment lactose with gas formation within 48
hours at 35 °C. Examples of coliform bacteria are members in the genera Escherichia ( e.g.
E. coli), Klebsiella (e.g. K. pneumoniae), Enterobacter (e.g. E. cloacai), and
Citrobacter ( e.g. C. freundii).
- colonization
- Multiplication of a microorganism after it has attached to host tissues or other surfaces.
- colony
- A macroscopically visible population of cells growing on solid medium, arising from a single
cell.
- colony-forming unit
- Any entity (usually a viable single cell) which can form a colony on an agar plate.
- cometabolism
- The metabolic transformation of a substance while a second substance serves as primary
energy or carbon source.
- commodity chemical
- Chemicals such as ethanol that have low monetary value and are thus sold primarily in bulk.
- common-source epidemic
- An epidemic resulting from infection of a large number of people from a single contaminated
source.
- compatible solute
- An organic compounds which serve as cytoplasmic solutes to balance water relations for
cells growing in environments of high salt or sugar.
- competence
- Ability to take up DNA and become genetically transformed.
- complement
- A complex of proteins in the blood serum that interacts sequentially with specific antibody in
certain kinds of antigen-antibody reactions.
- complement fixation
- The consumption of complement by an antibody-antigen reaction.
- complementary
- Nucleic acid sequences that can base pair with each other.
- complex medium
- A medium whose precise chemical composition is unknown. Also called undefined medium.
Compare with defined medium.
- concatamer
- A DNA molecule consisting of two or more separate molecules linked end-to-end to form a
long linear structure.
- conidiophore
- An aerial hypha bearing condiospores.
- conidiospore
- An asexual spore produced in a chain from a condiophore.
- conjugation
- In prokaryotes, transfer of genetic information from a donor cell to a recipient cell by
cell-to-cell contact.
- conjugative plasmid
- Self-transmissible plasmid; a plasmid which encodes all the functions needed for its own
intercellular transmission by conjugation.
- consensus sequence
- A nucleic acid sequence in which the base present in a given position is that base most
commonly found when many experimentally determined sequences are compared.
- consortium
- A two- (or more) membered bacterial culture (or natural assemblage) in which each
organism benefits from the other.
- contagious
- Of a disease, transmissible.
- copy number
- The number of copies of a plasmid per cell; also used to referred to the number of copies of
a gene (e.g. gene copy number).
- cortex
- The region inside the spore coat of an endospore, around the core.
- covalent
- A nonionic chemical bond formed by a sharing of electrons between two atoms.
- crista
- Inner membrane in a mitochondrion, site of respiration.
- culture
- A particular strain or kind of organism growing in a laboratory medium.
- culture medium
- See medium.
- cutaneous
- Relating to the skin.
- cyanobacterium
- A prokaryotic oxygenic phototrophic bacterium containing chlorophyll a and phycobilins.
- cyclic photophosphorylation
- The formation of ATP when light energy is used to move electrons cyclically through an
electron transport chain during photosynthesis; only photosystem I participates.
- Cyclospora cayetanensis
- Cyclospora cayetanensis is an acid-fast, coccidian-like, parasitic protozoa with the size of
8-10 micrometer in diameter. Cyclospora cayetanesis was recently recognized as a new
(intestinal) protozoan pathogen of human (1993, species name was proposed in 1994) and
was identified as the cause of the prolonged diarrhoea of travelers as well as
immunocompetent and immunocompromised patients.
- cyst
- A resting stage formed by some bacteria and protozoa in which the whole cell is surrounded
by a protective layer; not the same as spore.
- cytochrome
- Iron-containing porphyrin rings complexed with protiens, which act as electron carriers in the
electron-transport system.
- cytokine
- A small soluble protein from human cells in response to bacterial infection; directly or
indirectly may induce fever, pain, or T-cell proliferatio; produced by cells other than
lymphocytes, usually phagocytic cells.
- cytoplasm
- Cellular contents inside the cytoplasmic membrane, excluding the nucleus.
- cytoplasmic membrane
- The seletively permeable membrane surrounding the cell's cytoplasm; also called cell
membrane or plasma membrane.
Compiled by Tsute Chen, Converted by Ben Hoyt