Category: Biology Dictionary C

Chromatid Definition When a cell is preparing to divide, it makes a new copy of all of its DNA, so that the cell now possesses two copies of each chromosome. The two copies of the cell’s original chromosome are called “sister chromatids.” During anaphase of cell division, the two chromatids will be pulled apart, and […]

Chorion Definition The chorion is one of the membranes that surround the fetus while it is still being formed. In mammals, the fetus lies in the amniotic sac, which is formed by the chorion and the amnion and separates the embryo from the mother’s endometrium. During development, the embryo grows inside, and beside, four extraembryonic […]

Chordate Definition A chordate is an animal that belongs to the phylum Chordata, which is part of the Deuterostomes kingdom. Organisms in the Deuterostomes kingdom have a distinct characteristic: their anus develops before their mouth in early embryonic stages. The phylum Chordata includes a wide range of organisms, as it is comprised of all vertebrates, which are organisms with […]

Cholinergic Definition Cholinergic is a term used to refer to the molecule acetylcholine. It is usually employed to define neurons, receptors or synapses that use acetylcholine. For instance, a cholinergic neuron is a neuron that releases acetylcholine, and a cholinergic receptor is a receptor to which acetylcholine binds. Acetylcholine is a signal molecule in the […]

Chloroplast Definition The chloroplast, found only in algal and plant cells, is a cell organelle that produces energy through photosynthesis. The word chloroplast comes from the Greek words khloros, meaning “green”, and plastes, meaning “formed”. It has a high concentration of chlorophyll, the molecule that captures light energy, and this gives many plants and algae a green […]

Chlorophyll Definition Chlorophyll is a molecule produced by plants, algae and cyanobacteria which aids in the conversion of light energy into chemical bonds. Chlorophyll is known as a pigment, or molecule that reflects some wavelengths of light, while absorbing others. Pigments produce a variety of colors in the plant and animal world. Chlorophyll is a […]

Chitin Definition Chitin is a large, structural polysaccharide made from chains of modified glucose. Chitin is found in the exoskeletons of insects, the cell walls of fungi, and certain hard structures in invertebrates and fish. In terms of abundance, chitin is second to only cellulose. In the biosphere, over 1 billion tons of chitin are […]

Chemosynthesis Definition Chemosynthesis is the conversion of inorganic carbon-containing compounds into organic matter such as sugars and amino acids. Chemosynthesis uses energy from inorganic chemicals to perform this task. The inorganic “energy source” is usually a molecule that has electrons to spare, such as hydrogen gas, hydrogen sulfide, ammonia, or ferrous iron. Like photosynthesis and […]

Chemokines Definition Chemokines are signaling proteins secreted by cells of the immune system that stimulate the movement of other cells. Their name is reminiscent of their function since it is derived from chemotaxis, or movement in response to a chemical stimulus, and cytokines, which are small proteins implicated in cell signaling. That is, chemokines are cytokines that […]

Chemoheterotroph Definition It may surprise you to learn this, but you are actually a chemoheterotroph! “Chemoheterotroph” is the term for an organism which derives its energy from chemicals, and needs to consume other organisms in order to live. That means you: your body gets its energy from food, and you must consume other organisms such […]