Search results
Results from the WOW.Com Content Network
In chemistry, a precursor is a compound that participates in a chemical reaction that produces another compound. In biochemistry , the term "precursor" often refers more specifically to a chemical compound preceding another in a metabolic pathway , such as a protein precursor .
Precursor (physics), a phenomenon of wave propagation in dispersive media; Precursor in the course of a disease, a state preceding a particular stage in that course; Precursor cell (biology), a unipotent stem cell; Earthquake precursor, a diagnostic phenomenon that can occur before an earthquake; Gehrlein Precursor, a glider
Drug precursors, also referred to as precursor chemicals or simply precursors, are substances used to manufacture illicit drugs. Most precursors also have legitimate commercial uses and are legally used in a wide variety of industrial processes and consumer products, such as medicines, flavourings, and fragrances.
A protein precursor, also called a pro-protein or pro-peptide, is an inactive protein (or peptide) that can be turned into an active form by post-translational modification, such as breaking off a piece of the molecule or adding on another molecule. The name of the precursor for a protein is often prefixed by pro-.
In cell biology, precursor cells—also called blast cells—are partially differentiated, or intermediate, and are sometimes referred to as progenitor cells. A precursor cell is a stem cell with the capacity to differentiate into only one cell type, meaning they are unipotent stem cells .
Ribonucleotides can be synthesized in organisms from smaller molecules through the de novo pathway or recycled through the salvage pathway. In the case of the de novo pathway, both purines and pyrimidines are synthesized from components derived from precursors of amino acids, ribose-5-phosphates, CO 2, and NH 3. [17] [12] The synthesis of IMP.
Reaction with daylight ultraviolet (UV) rays and these precursors create ground-level ozone pollution (tropospheric ozone). Ozone is known to have the following health effects at concentrations common in urban air: Irritation of the respiratory system, causing coughing, throat irritation, and/or an uncomfortable sensation in the chest.
The particular type of precursor characterized by increasing period and amplitude is known as the high-frequency Sommerfeld precursor. In a region of anomalous dispersion, where low-frequency components have faster group velocities than high-frequency ones, the opposite of the above situation occurs: the onset of the precursor is characterized ...